diff --git a/build.xml b/build.xml
index 262dd20a..b3e9564a 100644
--- a/build.xml
+++ b/build.xml
@@ -190,13 +190,13 @@
       <module namespace="jetbrains.mps.logic.test" type="solution" uuid="b189d6c6-9397-4d64-88af-1ac73760a4f5">
         <dependencies>
           <module ref="6354ebe7-c22a-4a0f-ac54-50b52ab9b065(JDK)" />
+          <module ref="49808fad-9d41-4b96-83fa-9231640f6b2b(JUnit)" />
           <module ref="6ed54515-acc8-4d1e-a16c-9fd6cfe951ea(MPS.Core)" />
           <module ref="8865b7a8-5271-43d3-884c-6fd1d9cfdd34(MPS.OpenAPI)" />
           <module ref="4c6a28d1-2c60-478d-b36e-db9b3cbb21fb(closures.runtime)" />
           <module ref="9b80526e-f0bf-4992-bdf5-cee39c1833f3(collections.runtime)" />
           <module ref="a3e4657f-a76c-45bb-bbda-c764596ecc65(jetbrains.mps.baseLanguage.logging.runtime)" />
           <module ref="d44dab97-aaac-44cb-9745-8a14db674c03(jetbrains.mps.baseLanguage.tuples.runtime)" />
-          <module ref="83f155ff-422c-4b5a-a2f2-b459302dd215(jetbrains.mps.baseLanguage.unitTest.libs)" />
           <module ref="d936855b-48da-4812-a8a0-2bfddd633ac5(jetbrains.mps.lang.behavior.api)" />
           <module ref="d936855b-48da-4812-a8a0-2bfddd633ac4(jetbrains.mps.lang.behavior.runtime)" />
           <module ref="a5478664-6b44-4c62-a9f7-434f8aa57eee(jetbrains.mps.logic.runtime)" />
@@ -497,13 +497,13 @@
       <module namespace="jetbrains.mps.lang.typechecking.test" type="solution" uuid="c9670c16-a215-41fb-8784-04b14329799d">
         <dependencies>
           <module ref="6354ebe7-c22a-4a0f-ac54-50b52ab9b065(JDK)" />
+          <module ref="49808fad-9d41-4b96-83fa-9231640f6b2b(JUnit)" />
           <module ref="6ed54515-acc8-4d1e-a16c-9fd6cfe951ea(MPS.Core)" />
           <module ref="1ed103c3-3aa6-49b7-9c21-6765ee11f224(MPS.Editor)" />
           <module ref="8865b7a8-5271-43d3-884c-6fd1d9cfdd34(MPS.OpenAPI)" />
           <module ref="4c6a28d1-2c60-478d-b36e-db9b3cbb21fb(closures.runtime)" />
           <module ref="9b80526e-f0bf-4992-bdf5-cee39c1833f3(collections.runtime)" />
           <module ref="a3e4657f-a76c-45bb-bbda-c764596ecc65(jetbrains.mps.baseLanguage.logging.runtime)" />
-          <module ref="83f155ff-422c-4b5a-a2f2-b459302dd215(jetbrains.mps.baseLanguage.unitTest.libs)" />
           <module ref="2d3c70e9-aab2-4870-8d8d-6036800e4103(jetbrains.mps.kernel)" />
           <module ref="d936855b-48da-4812-a8a0-2bfddd633ac5(jetbrains.mps.lang.behavior.api)" />
           <module ref="d936855b-48da-4812-a8a0-2bfddd633ac4(jetbrains.mps.lang.behavior.runtime)" />
@@ -587,11 +587,11 @@
       <module namespace="jetbrains.mps.baseLanguageExt.test" type="solution" uuid="e44e7802-2e40-482b-9b1c-6d42660a6a11">
         <dependencies>
           <module ref="6354ebe7-c22a-4a0f-ac54-50b52ab9b065(JDK)" />
+          <module ref="49808fad-9d41-4b96-83fa-9231640f6b2b(JUnit)" />
           <module ref="6ed54515-acc8-4d1e-a16c-9fd6cfe951ea(MPS.Core)" />
           <module ref="8865b7a8-5271-43d3-884c-6fd1d9cfdd34(MPS.OpenAPI)" />
           <module ref="4c6a28d1-2c60-478d-b36e-db9b3cbb21fb(closures.runtime)" />
           <module ref="9b80526e-f0bf-4992-bdf5-cee39c1833f3(collections.runtime)" />
-          <module ref="83f155ff-422c-4b5a-a2f2-b459302dd215(jetbrains.mps.baseLanguage.unitTest.libs)" />
           <module ref="d936855b-48da-4812-a8a0-2bfddd633ac5(jetbrains.mps.lang.behavior.api)" />
           <module ref="d936855b-48da-4812-a8a0-2bfddd633ac4(jetbrains.mps.lang.behavior.runtime)" />
           <module ref="e55e6749-03cb-4ea7-9695-2322bab791c1(jetbrains.mps.lang.test.matcher)" />
@@ -662,11 +662,11 @@
       <module namespace="jetbrains.mps.typechecking.sample.test" type="solution" uuid="1b65dfe8-24ff-41c3-9a3e-70f102942455">
         <dependencies>
           <module ref="6354ebe7-c22a-4a0f-ac54-50b52ab9b065(JDK)" />
+          <module ref="49808fad-9d41-4b96-83fa-9231640f6b2b(JUnit)" />
           <module ref="6ed54515-acc8-4d1e-a16c-9fd6cfe951ea(MPS.Core)" />
           <module ref="8865b7a8-5271-43d3-884c-6fd1d9cfdd34(MPS.OpenAPI)" />
           <module ref="4c6a28d1-2c60-478d-b36e-db9b3cbb21fb(closures.runtime)" />
           <module ref="9b80526e-f0bf-4992-bdf5-cee39c1833f3(collections.runtime)" />
-          <module ref="83f155ff-422c-4b5a-a2f2-b459302dd215(jetbrains.mps.baseLanguage.unitTest.libs)" />
           <module ref="2d3c70e9-aab2-4870-8d8d-6036800e4103(jetbrains.mps.kernel)" />
           <module ref="d936855b-48da-4812-a8a0-2bfddd633ac5(jetbrains.mps.lang.behavior.api)" />
           <module ref="d936855b-48da-4812-a8a0-2bfddd633ac4(jetbrains.mps.lang.behavior.runtime)" />
@@ -1400,7 +1400,6 @@
       <library file="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguage.regexp.runtime.jar" />
       <library file="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguage.scopes.jar" />
       <library file="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguage.tuples.jar" />
-      <library file="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguage.unitTest.libs/jetbrains.mps.baseLanguage.unitTest.libs.jar" />
       <library file="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguageInternal.jar" />
       <library file="${artifacts.mps}/languages/devkits/jetbrains.mps.devkit.language-descriptor.devkit" />
       <library file="${artifacts.mps}/languages/languageDesign/jetbrains.mps.baseLanguage.lightweightdsl.jar" />
@@ -1457,6 +1456,7 @@
       <library file="${artifacts.mps}/lib/mps-environment.jar" />
       <library file="${artifacts.mps}/lib/mps-openapi.jar" />
       <library file="${artifacts.mps}/lib/mps-platform.jar" />
+      <library file="${artifacts.mps}/lib/mps-stubs.jar" />
       <library file="${artifacts.mps}/lib/mps-test.jar" />
       <library file="${artifacts.mps}/lib/mps-tool.jar" />
       <library file="${artifacts.mps}/lib/mps-tuples.jar" />
@@ -1708,19 +1708,12 @@
         <fileset file="${mps.macro.logic_home}/logic/solutions/jetbrains.mps.logic.test/lib/mockito-core-2.0.3-beta.jar" />
         <fileset file="${mps.macro.logic_home}/logic/solutions/jetbrains.mps.logic.test/lib/objenesis-2.1.jar" />
         <fileset file="${artifacts.mps}/lib/junit-4.12.jar" />
-        <fileset file="${artifacts.mps}/lib/hamcrest-core-1.3.jar" />
         <fileset file="${artifacts.mps}/lib/annotations.jar" />
         <fileset file="${artifacts.mps}/lib/log4j.jar" />
         <fileset file="${artifacts.mps}/lib/jdom.jar" />
         <fileset file="${artifacts.mps}/lib/trove4j.jar" />
         <fileset file="${artifacts.mps}/lib/ecj-4.6.2.jar" />
         <fileset file="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguage.logging.runtime.jar" />
-        <fileset file="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguage.unitTest.libs/hamcrest-library-1.3.jar" />
-        <fileset file="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguage.unitTest.libs/hamcrest-library-1.3-sources.jar" />
-        <fileset file="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguage.unitTest.libs/jmock-2.8.2-sources.jar" />
-        <fileset file="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguage.unitTest.libs/jmock-2.8.2.jar" />
-        <fileset file="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguage.unitTest.libs/jmock-junit4-2.8.2-sources.jar" />
-        <fileset file="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguage.unitTest.libs/jmock-junit4-2.8.2.jar" />
       </classpath>
     </javac>
   </target>
@@ -2092,7 +2085,6 @@
         <fileset file="${mps.macro.logic_home}/typechecking/solutions/jetbrains.mps.typechecking/lib/rxjava2-swing-0.2.1.jar" />
         <fileset file="${artifacts.mps}/lib/ant/lib/ant.jar" />
         <fileset file="${artifacts.mps}/lib/junit-4.12.jar" />
-        <fileset file="${artifacts.mps}/lib/hamcrest-core-1.3.jar" />
         <fileset file="${artifacts.mps}/lib/annotations.jar" />
         <fileset file="${artifacts.mps}/lib/log4j.jar" />
         <fileset file="${artifacts.mps}/lib/jdom.jar" />
@@ -2114,12 +2106,6 @@
         <fileset file="${artifacts.mps}/plugins/mps-testing/languages/languageDesign/jetbrains.mps.lang.test.matcher.jar" />
         <fileset file="${artifacts.mps}/plugins/mps-testing/languages/languageDesign/jetbrains.mps.lang.test.runtime.jar" />
         <fileset file="${artifacts.mps}/languages/languageDesign/jetbrains.mps.lang.traceable.jar" />
-        <fileset file="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguage.unitTest.libs/hamcrest-library-1.3.jar" />
-        <fileset file="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguage.unitTest.libs/hamcrest-library-1.3-sources.jar" />
-        <fileset file="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguage.unitTest.libs/jmock-2.8.2-sources.jar" />
-        <fileset file="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguage.unitTest.libs/jmock-2.8.2.jar" />
-        <fileset file="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguage.unitTest.libs/jmock-junit4-2.8.2-sources.jar" />
-        <fileset file="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguage.unitTest.libs/jmock-junit4-2.8.2.jar" />
       </classpath>
     </javac>
   </target>
@@ -2383,7 +2369,6 @@
         <fileset file="${mps.macro.logic_home}/logic/solutions/jetbrains.mps.logic.test/lib/objenesis-2.1.jar" />
         <fileset file="${artifacts.mps}/lib/ant/lib/ant.jar" />
         <fileset file="${artifacts.mps}/lib/junit-4.12.jar" />
-        <fileset file="${artifacts.mps}/lib/hamcrest-core-1.3.jar" />
         <fileset file="${artifacts.mps}/lib/annotations.jar" />
         <fileset file="${artifacts.mps}/lib/log4j.jar" />
         <fileset file="${artifacts.mps}/lib/jdom.jar" />
@@ -2405,12 +2390,6 @@
         <fileset file="${artifacts.mps}/plugins/mps-testing/languages/languageDesign/jetbrains.mps.lang.test.matcher.jar" />
         <fileset file="${artifacts.mps}/plugins/mps-testing/languages/languageDesign/jetbrains.mps.lang.test.runtime.jar" />
         <fileset file="${artifacts.mps}/languages/languageDesign/jetbrains.mps.lang.traceable.jar" />
-        <fileset file="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguage.unitTest.libs/hamcrest-library-1.3.jar" />
-        <fileset file="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguage.unitTest.libs/hamcrest-library-1.3-sources.jar" />
-        <fileset file="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguage.unitTest.libs/jmock-2.8.2-sources.jar" />
-        <fileset file="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguage.unitTest.libs/jmock-2.8.2.jar" />
-        <fileset file="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguage.unitTest.libs/jmock-junit4-2.8.2-sources.jar" />
-        <fileset file="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguage.unitTest.libs/jmock-junit4-2.8.2.jar" />
       </classpath>
     </javac>
   </target>
@@ -2454,7 +2433,6 @@
         <fileset file="${mps.macro.logic_home}/typechecking/solutions/jetbrains.mps.typechecking/lib/rxjava2-swing-0.2.1.jar" />
         <fileset file="${artifacts.mps}/lib/ant/lib/ant.jar" />
         <fileset file="${artifacts.mps}/lib/junit-4.12.jar" />
-        <fileset file="${artifacts.mps}/lib/hamcrest-core-1.3.jar" />
         <fileset file="${artifacts.mps}/lib/annotations.jar" />
         <fileset file="${artifacts.mps}/lib/log4j.jar" />
         <fileset file="${artifacts.mps}/lib/jdom.jar" />
@@ -2475,12 +2453,6 @@
         <fileset file="${artifacts.mps}/plugins/mps-testing/languages/languageDesign/jetbrains.mps.lang.test.matcher.jar" />
         <fileset file="${artifacts.mps}/plugins/mps-testing/languages/languageDesign/jetbrains.mps.lang.test.runtime.jar" />
         <fileset file="${artifacts.mps}/languages/languageDesign/jetbrains.mps.lang.traceable.jar" />
-        <fileset file="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguage.unitTest.libs/hamcrest-library-1.3.jar" />
-        <fileset file="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguage.unitTest.libs/hamcrest-library-1.3-sources.jar" />
-        <fileset file="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguage.unitTest.libs/jmock-2.8.2-sources.jar" />
-        <fileset file="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguage.unitTest.libs/jmock-2.8.2.jar" />
-        <fileset file="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguage.unitTest.libs/jmock-junit4-2.8.2-sources.jar" />
-        <fileset file="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguage.unitTest.libs/jmock-junit4-2.8.2.jar" />
       </classpath>
     </javac>
   </target>
@@ -2501,7 +2473,6 @@
       <pathelement location="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguage.regexp.runtime.jar" />
       <pathelement location="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguage.scopes.jar" />
       <pathelement location="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguage.tuples.jar" />
-      <pathelement location="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguage.unitTest.libs/jetbrains.mps.baseLanguage.unitTest.libs.jar" />
       <pathelement location="${artifacts.mps}/languages/baseLanguage/jetbrains.mps.baseLanguageInternal.jar" />
       <pathelement location="${artifacts.mps}/languages/devkits/jetbrains.mps.devkit.language-descriptor.devkit" />
       <pathelement location="${artifacts.mps}/languages/languageDesign/jetbrains.mps.baseLanguage.lightweightdsl.jar" />
@@ -2548,6 +2519,7 @@
       <pathelement location="${artifacts.mps}/lib/mps-environment.jar" />
       <pathelement location="${artifacts.mps}/lib/mps-openapi.jar" />
       <pathelement location="${artifacts.mps}/lib/mps-platform.jar" />
+      <pathelement location="${artifacts.mps}/lib/mps-stubs.jar" />
       <pathelement location="${artifacts.mps}/lib/mps-test.jar" />
       <pathelement location="${artifacts.mps}/lib/mps-tool.jar" />
       <pathelement location="${artifacts.mps}/lib/mps-tuples.jar" />
diff --git a/typechecking/solutions/jetbrains.mps.typechecking.ui/models/ui.plugin.mps b/typechecking/solutions/jetbrains.mps.typechecking.ui/models/ui.plugin.mps
index 20f73fdf..4f8924a9 100644
--- a/typechecking/solutions/jetbrains.mps.typechecking.ui/models/ui.plugin.mps
+++ b/typechecking/solutions/jetbrains.mps.typechecking.ui/models/ui.plugin.mps
@@ -88,6 +88,11 @@
     <import index="d6hs" ref="6ed54515-acc8-4d1e-a16c-9fd6cfe951ea/java:jetbrains.mps.errors.item(MPS.Core/)" />
     <import index="tj24" ref="r:0fbbb63a-fd15-46e1-8136-78049f6d6e63(jetbrains.mps.typechecking.service)" />
     <import index="6pyv" ref="r:e418ad23-36dc-4ed0-b837-26a7fd157da3(jetbrains.mps.lang.typesystem2.program)" />
+    <import index="iljd" ref="6998f568-f0e9-473b-b4a8-9efb6499fc8d/java:io.reactivex.plugins(jetbrains.mps.typechecking/)" />
+    <import index="5tvg" ref="6998f568-f0e9-473b-b4a8-9efb6499fc8d/java:io.reactivex.disposables(jetbrains.mps.typechecking/)" />
+    <import index="al1t" ref="498d89d2-c2e9-11e2-ad49-6cf049e62fe5/java:com.intellij.diagnostic(MPS.IDEA/)" />
+    <import index="uzhr" ref="498d89d2-c2e9-11e2-ad49-6cf049e62fe5/java:com.intellij.openapi.diagnostic(MPS.IDEA/)" />
+    <import index="7ce3" ref="6998f568-f0e9-473b-b4a8-9efb6499fc8d/java:io.reactivex.exceptions(jetbrains.mps.typechecking/)" />
     <import index="zn9m" ref="498d89d2-c2e9-11e2-ad49-6cf049e62fe5/java:com.intellij.openapi.util(MPS.IDEA/)" implicit="true" />
   </imports>
   <registry>
@@ -487,6 +492,7 @@
       </concept>
       <concept id="1170345865475" name="jetbrains.mps.baseLanguage.structure.AnonymousClass" flags="ig" index="1Y3b0j">
         <reference id="1170346070688" name="classifier" index="1Y3XeK" />
+        <child id="1201186121363" name="typeParameter" index="2Ghqu4" />
       </concept>
       <concept id="8064396509828172209" name="jetbrains.mps.baseLanguage.structure.UnaryMinus" flags="nn" index="1ZRNhn" />
     </language>
@@ -26574,6 +26580,271 @@
     <property role="TrG5h" value="SchedulerLifecycle" />
     <node concept="2uRRBj" id="2mbQB8J3MMu" role="2uRRBE">
       <node concept="3clFbS" id="2mbQB8J3MMv" role="2VODD2">
+        <node concept="3clFbH" id="19wqdqNVq8I" role="3cqZAp" />
+        <node concept="3clFbF" id="19wqdqNXqO9" role="3cqZAp">
+          <node concept="2YIFZM" id="19wqdqNXqYM" role="3clFbG">
+            <ref role="37wK5l" to="iljd:~RxJavaPlugins.setOnSingleSubscribe(io.reactivex.functions.BiFunction):void" resolve="setOnSingleSubscribe" />
+            <ref role="1Pybhc" to="iljd:~RxJavaPlugins" resolve="RxJavaPlugins" />
+            <node concept="1bVj0M" id="19wqdqNXr4e" role="37wK5m">
+              <node concept="37vLTG" id="19wqdqNXr9q" role="1bW2Oz">
+                <property role="TrG5h" value="single" />
+                <property role="3TUv4t" value="true" />
+                <node concept="3uibUv" id="19wqdqNX$Yy" role="1tU5fm">
+                  <ref role="3uigEE" to="unkn:~Single" resolve="Single" />
+                </node>
+              </node>
+              <node concept="37vLTG" id="19wqdqNX_ay" role="1bW2Oz">
+                <property role="TrG5h" value="singleObserver" />
+                <property role="3TUv4t" value="true" />
+                <node concept="3uibUv" id="19wqdqNX_oI" role="1tU5fm">
+                  <ref role="3uigEE" to="unkn:~SingleObserver" resolve="SingleObserver" />
+                </node>
+              </node>
+              <node concept="3clFbS" id="19wqdqNXr4f" role="1bW5cS">
+                <node concept="3clFbF" id="19wqdqNXA2j" role="3cqZAp">
+                  <node concept="2ShNRf" id="19wqdqNXA2f" role="3clFbG">
+                    <node concept="YeOm9" id="19wqdqNXBxp" role="2ShVmc">
+                      <node concept="1Y3b0j" id="19wqdqNXBxs" role="YeSDq">
+                        <property role="2bfB8j" value="true" />
+                        <ref role="1Y3XeK" to="unkn:~SingleObserver" resolve="SingleObserver" />
+                        <ref role="37wK5l" to="wyt6:~Object.&lt;init&gt;()" resolve="Object" />
+                        <node concept="3Tm1VV" id="19wqdqNXBxt" role="1B3o_S" />
+                        <node concept="3clFb_" id="19wqdqNXBxu" role="jymVt">
+                          <property role="1EzhhJ" value="false" />
+                          <property role="TrG5h" value="onSubscribe" />
+                          <property role="DiZV1" value="false" />
+                          <property role="od$2w" value="false" />
+                          <node concept="3Tm1VV" id="19wqdqNXBxv" role="1B3o_S" />
+                          <node concept="3cqZAl" id="19wqdqNXBxx" role="3clF45" />
+                          <node concept="37vLTG" id="19wqdqNXBxy" role="3clF46">
+                            <property role="TrG5h" value="disposable" />
+                            <node concept="3uibUv" id="19wqdqNXBxz" role="1tU5fm">
+                              <ref role="3uigEE" to="5tvg:~Disposable" resolve="Disposable" />
+                            </node>
+                          </node>
+                          <node concept="3clFbS" id="19wqdqNXBx_" role="3clF47">
+                            <node concept="3clFbF" id="19wqdqNXE92" role="3cqZAp">
+                              <node concept="2OqwBi" id="19wqdqNXEex" role="3clFbG">
+                                <node concept="37vLTw" id="19wqdqNXE91" role="2Oq$k0">
+                                  <ref role="3cqZAo" node="19wqdqNX_ay" resolve="singleObserver" />
+                                </node>
+                                <node concept="liA8E" id="19wqdqNXEvz" role="2OqNvi">
+                                  <ref role="37wK5l" to="unkn:~SingleObserver.onSubscribe(io.reactivex.disposables.Disposable):void" resolve="onSubscribe" />
+                                  <node concept="37vLTw" id="19wqdqNXF0M" role="37wK5m">
+                                    <ref role="3cqZAo" node="19wqdqNXBxy" resolve="disposable" />
+                                  </node>
+                                </node>
+                              </node>
+                            </node>
+                          </node>
+                        </node>
+                        <node concept="2tJIrI" id="19wqdqO0$1k" role="jymVt" />
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+                  </node>
+                </node>
+              </node>
+            </node>
+          </node>
+        </node>
+      </node>
+      <node concept="3cqZAl" id="19wqdqO0ZPt" role="3clF45" />
+      <node concept="3Tm1VV" id="19wqdqO0ZPu" role="1B3o_S" />
+    </node>
+    <node concept="2tJIrI" id="19wqdqO0ZC0" role="jymVt" />
+    <node concept="3Tm1VV" id="19wqdqO0ZBd" role="1B3o_S" />
+  </node>
 </model>
 
diff --git a/typechecking/solutions/jetbrains.mps.typechecking/models/service.mps b/typechecking/solutions/jetbrains.mps.typechecking/models/service.mps
index 83170501..d9abb093 100644
--- a/typechecking/solutions/jetbrains.mps.typechecking/models/service.mps
+++ b/typechecking/solutions/jetbrains.mps.typechecking/models/service.mps
@@ -42,6 +42,8 @@
     <import index="qox2" ref="r:7ff0776c-aea4-4df2-88a3-2efb6b568dc3(jetbrains.mps.typechecking.plugin)" />
     <import index="f4yq" ref="6998f568-f0e9-473b-b4a8-9efb6499fc8d/java:hu.akarnokd.rxjava2.swing(jetbrains.mps.typechecking/)" />
     <import index="6pyv" ref="r:e418ad23-36dc-4ed0-b837-26a7fd157da3(jetbrains.mps.lang.typesystem2.program)" />
+    <import index="e5vs" ref="498d89d2-c2e9-11e2-ad49-6cf049e62fe5/java:org.jetbrains.ide(MPS.IDEA/)" />
+    <import index="ixe9" ref="498d89d2-c2e9-11e2-ad49-6cf049e62fe5/java:com.intellij.util.concurrency(MPS.IDEA/)" />
   </imports>
   <registry>
     <language id="a247e09e-2435-45ba-b8d2-07e93feba96a" name="jetbrains.mps.baseLanguage.tuples">
@@ -800,8 +802,8 @@
                                 <node concept="liA8E" id="443LGHBQr4s" role="2OqNvi">
                                   <ref role="37wK5l" node="2mbQB8J5m$l" resolve="scheduleExecute" />
                                   <node concept="2YIFZM" id="3KwBCAACgvt" role="37wK5m">
-                                    <ref role="37wK5l" node="3KwBCAA_erO" resolve="single" />
                                     <ref role="1Pybhc" node="3KwBCAA_ela" resolve="TypecheckingSchedulers" />
+                                    <ref role="37wK5l" node="3KwBCAA_erO" resolve="blocking" />
                                   </node>
                                 </node>
                               </node>
@@ -2190,9 +2192,9 @@
         <node concept="3clFbF" id="Hg6EndD1pg" role="3cqZAp">
           <node concept="1rXfSq" id="Hg6EndD1pf" role="3clFbG">
             <ref role="37wK5l" node="2mbQB8J5m$l" resolve="scheduleExecute" />
-            <node concept="2YIFZM" id="Hg6EndD1UU" role="37wK5m">
-              <ref role="1Pybhc" to="m4y7:~Schedulers" resolve="Schedulers" />
-              <ref role="37wK5l" to="m4y7:~Schedulers.single():io.reactivex.Scheduler" resolve="single" />
+            <node concept="2YIFZM" id="19wqdqO46s4" role="37wK5m">
+              <ref role="37wK5l" node="19wqdqO45_Z" resolve="background" />
+              <ref role="1Pybhc" node="3KwBCAA_ela" resolve="TypecheckingSchedulers" />
             </node>
           </node>
         </node>
@@ -2300,81 +2302,89 @@
           </node>
         </node>
         <node concept="3clFbF" id="6kREIVkBx2c" role="3cqZAp">
-          <node concept="2OqwBi" id="4BHjwwGLnhh" role="3clFbG">
-            <node concept="37vLTw" id="4BHjwwGi7IH" role="2Oq$k0">
-              <ref role="3cqZAo" node="4BHjwwGi7In" resolve="last" />
-            </node>
-            <node concept="liA8E" id="4BHjwwGLnNl" role="2OqNvi">
-              <ref role="37wK5l" to="unkn:~Single.map(io.reactivex.functions.Function):io.reactivex.Single" resolve="map" />
-              <node concept="1bVj0M" id="4BHjwwGLp1f" role="37wK5m">
-                <node concept="37vLTG" id="4BHjwwGLq3q" role="1bW2Oz">
-                  <property role="TrG5h" value="step" />
-                  <node concept="3uibUv" id="4BHjwwGLqs3" role="1tU5fm">
-                    <ref role="3uigEE" node="1pPth$lAzAx" resolve="Step" />
-                    <node concept="3qTvmN" id="4BHjwwGLqPZ" role="11_B2D" />
-                  </node>
-                </node>
-                <node concept="3clFbS" id="4BHjwwGLp1g" role="1bW5cS">
-                  <node concept="3clFbJ" id="4BHjwwGLrnj" role="3cqZAp">
-                    <node concept="3y3z36" id="4BHjwwGLrZU" role="3clFbw">
-                      <node concept="10Nm6u" id="4BHjwwGLsfX" role="3uHU7w" />
-                      <node concept="37vLTw" id="4BHjwwGLrAa" role="3uHU7B">
-                        <ref role="3cqZAo" node="4BHjwwGKJA$" resolve="failure" />
-                      </node>
+          <node concept="2OqwBi" id="19wqdqNSOz_" role="3clFbG">
+            <node concept="2OqwBi" id="4BHjwwGLnhh" role="2Oq$k0">
+              <node concept="37vLTw" id="4BHjwwGi7IH" role="2Oq$k0">
+                <ref role="3cqZAo" node="4BHjwwGi7In" resolve="last" />
+              </node>
+              <node concept="liA8E" id="4BHjwwGLnNl" role="2OqNvi">
+                <ref role="37wK5l" to="unkn:~Single.map(io.reactivex.functions.Function):io.reactivex.Single" resolve="map" />
+                <node concept="1bVj0M" id="4BHjwwGLp1f" role="37wK5m">
+                  <node concept="37vLTG" id="4BHjwwGLq3q" role="1bW2Oz">
+                    <property role="TrG5h" value="step" />
+                    <node concept="3uibUv" id="4BHjwwGLqs3" role="1tU5fm">
+                      <ref role="3uigEE" node="1pPth$lAzAx" resolve="Step" />
+                      <node concept="3qTvmN" id="4BHjwwGLqPZ" role="11_B2D" />
                     </node>
-                    <node concept="3clFbS" id="4BHjwwGLrnl" role="3clFbx">
-                      <node concept="3clFbJ" id="4BHjwwGLT5a" role="3cqZAp">
-                        <node concept="3clFbS" id="4BHjwwGLT5c" role="3clFbx">
-                          <node concept="YS8fn" id="4BHjwwGLswN" role="3cqZAp">
-                            <node concept="1eOMI4" id="4BHjwwGMaLB" role="YScLw">
-                              <node concept="10QFUN" id="4BHjwwGMaL$" role="1eOMHV">
-                                <node concept="3uibUv" id="4BHjwwGMaLD" role="10QFUM">
-                                  <ref role="3uigEE" to="wyt6:~Exception" resolve="Exception" />
-                                </node>
-                                <node concept="37vLTw" id="4BHjwwGMaLE" role="10QFUP">
-                                  <ref role="3cqZAo" node="4BHjwwGKJA$" resolve="failure" />
-                                </node>
-                              </node>
-                            </node>
-                          </node>
-                          <node concept="3clFbH" id="4BHjwwGLZ5i" role="3cqZAp" />
+                  </node>
+                  <node concept="3clFbS" id="4BHjwwGLp1g" role="1bW5cS">
+                    <node concept="3clFbJ" id="4BHjwwGLrnj" role="3cqZAp">
+                      <node concept="3y3z36" id="4BHjwwGLrZU" role="3clFbw">
+                        <node concept="10Nm6u" id="4BHjwwGLsfX" role="3uHU7w" />
+                        <node concept="37vLTw" id="4BHjwwGLrAa" role="3uHU7B">
+                          <ref role="3cqZAo" node="4BHjwwGKJA$" resolve="failure" />
                         </node>
-                        <node concept="2ZW3vV" id="4BHjwwGLTOA" role="3clFbw">
-                          <node concept="3uibUv" id="4BHjwwGLU7V" role="2ZW6by">
-                            <ref role="3uigEE" to="wyt6:~Exception" resolve="Exception" />
-                          </node>
-                          <node concept="37vLTw" id="4BHjwwGLTjT" role="2ZW6bz">
-                            <ref role="3cqZAo" node="4BHjwwGKJA$" resolve="failure" />
-                          </node>
-                        </node>
-                        <node concept="9aQIb" id="4BHjwwGLUI6" role="9aQIa">
-                          <node concept="3clFbS" id="4BHjwwGLUI7" role="9aQI4">
-                            <node concept="YS8fn" id="4BHjwwGLUY4" role="3cqZAp">
-                              <node concept="2ShNRf" id="4BHjwwGLVh3" role="YScLw">
-                                <node concept="1pGfFk" id="4BHjwwGLWeu" role="2ShVmc">
-                                  <ref role="37wK5l" to="wyt6:~RuntimeException.&lt;init&gt;(java.lang.String,java.lang.Throwable)" resolve="RuntimeException" />
-                                  <node concept="Xl_RD" id="4BHjwwGLWTc" role="37wK5m">
-                                    <property role="Xl_RC" value="unexpected failure" />
+                      </node>
+                      <node concept="3clFbS" id="4BHjwwGLrnl" role="3clFbx">
+                        <node concept="3clFbJ" id="4BHjwwGLT5a" role="3cqZAp">
+                          <node concept="3clFbS" id="4BHjwwGLT5c" role="3clFbx">
+                            <node concept="YS8fn" id="4BHjwwGLswN" role="3cqZAp">
+                              <node concept="1eOMI4" id="4BHjwwGMaLB" role="YScLw">
+                                <node concept="10QFUN" id="4BHjwwGMaL$" role="1eOMHV">
+                                  <node concept="3uibUv" id="4BHjwwGMaLD" role="10QFUM">
+                                    <ref role="3uigEE" to="wyt6:~Exception" resolve="Exception" />
                                   </node>
-                                  <node concept="37vLTw" id="4BHjwwGLYSe" role="37wK5m">
+                                  <node concept="37vLTw" id="4BHjwwGMaLE" role="10QFUP">
                                     <ref role="3cqZAo" node="4BHjwwGKJA$" resolve="failure" />
                                   </node>
                                 </node>
                               </node>
                             </node>
+                            <node concept="3clFbH" id="4BHjwwGLZ5i" role="3cqZAp" />
+                          </node>
+                          <node concept="2ZW3vV" id="4BHjwwGLTOA" role="3clFbw">
+                            <node concept="3uibUv" id="4BHjwwGLU7V" role="2ZW6by">
+                              <ref role="3uigEE" to="wyt6:~Exception" resolve="Exception" />
+                            </node>
+                            <node concept="37vLTw" id="4BHjwwGLTjT" role="2ZW6bz">
+                              <ref role="3cqZAo" node="4BHjwwGKJA$" resolve="failure" />
+                            </node>
+                          </node>
+                          <node concept="9aQIb" id="4BHjwwGLUI6" role="9aQIa">
+                            <node concept="3clFbS" id="4BHjwwGLUI7" role="9aQI4">
+                              <node concept="YS8fn" id="4BHjwwGLUY4" role="3cqZAp">
+                                <node concept="2ShNRf" id="4BHjwwGLVh3" role="YScLw">
+                                  <node concept="1pGfFk" id="4BHjwwGLWeu" role="2ShVmc">
+                                    <ref role="37wK5l" to="wyt6:~RuntimeException.&lt;init&gt;(java.lang.String,java.lang.Throwable)" resolve="RuntimeException" />
+                                    <node concept="Xl_RD" id="4BHjwwGLWTc" role="37wK5m">
+                                      <property role="Xl_RC" value="unexpected failure" />
+                                    </node>
+                                    <node concept="37vLTw" id="4BHjwwGLYSe" role="37wK5m">
+                                      <ref role="3cqZAo" node="4BHjwwGKJA$" resolve="failure" />
+                                    </node>
+                                  </node>
+                                </node>
+                              </node>
+                            </node>
                           </node>
                         </node>
                       </node>
                     </node>
-                  </node>
-                  <node concept="3clFbF" id="4BHjwwGLtiL" role="3cqZAp">
-                    <node concept="37vLTw" id="4BHjwwGLtiJ" role="3clFbG">
-                      <ref role="3cqZAo" node="4BHjwwGLq3q" resolve="step" />
+                    <node concept="3clFbF" id="4BHjwwGLtiL" role="3cqZAp">
+                      <node concept="37vLTw" id="4BHjwwGLtiJ" role="3clFbG">
+                        <ref role="3cqZAo" node="4BHjwwGLq3q" resolve="step" />
+                      </node>
                     </node>
                   </node>
                 </node>
               </node>
             </node>
+            <node concept="liA8E" id="19wqdqNSTzi" role="2OqNvi">
+              <ref role="37wK5l" to="unkn:~Single.subscribeOn(io.reactivex.Scheduler):io.reactivex.Single" resolve="subscribeOn" />
+              <node concept="37vLTw" id="19wqdqNSVSy" role="37wK5m">
+                <ref role="3cqZAo" node="2mbQB8J5_aK" resolve="subscribeScheduler" />
+              </node>
+            </node>
           </node>
         </node>
       </node>
@@ -6124,9 +6134,9 @@
                 </node>
                 <node concept="liA8E" id="4BHjwwGP7Ac" role="2OqNvi">
                   <ref role="37wK5l" node="2mbQB8J5m$l" resolve="scheduleExecute" />
-                  <node concept="2YIFZM" id="4BHjwwGP7Ad" role="37wK5m">
-                    <ref role="37wK5l" to="m4y7:~Schedulers.single():io.reactivex.Scheduler" resolve="single" />
-                    <ref role="1Pybhc" to="m4y7:~Schedulers" resolve="Schedulers" />
+                  <node concept="2YIFZM" id="19wqdqOakA2" role="37wK5m">
+                    <ref role="37wK5l" node="3KwBCAA_erO" resolve="blocking" />
+                    <ref role="1Pybhc" node="3KwBCAA_ela" resolve="TypecheckingSchedulers" />
                   </node>
                 </node>
               </node>
@@ -7766,8 +7776,30 @@
     <property role="3GE5qa" value="launch" />
     <property role="TrG5h" value="TypecheckingSchedulers" />
     <node concept="2tJIrI" id="3KwBCAA_el$" role="jymVt" />
+    <node concept="2YIFZL" id="19wqdqO45_Z" role="jymVt">
+      <property role="DiZV1" value="false" />
+      <property role="od$2w" value="false" />
+      <property role="TrG5h" value="background" />
+      <node concept="3clFbS" id="19wqdqO45zl" role="3clF47">
+        <node concept="3clFbF" id="19wqdqO45Oo" role="3cqZAp">
+          <node concept="2YIFZM" id="19wqdqO45Oq" role="3clFbG">
+            <ref role="1Pybhc" to="m4y7:~Schedulers" resolve="Schedulers" />
+            <ref role="37wK5l" to="m4y7:~Schedulers.from(java.util.concurrent.Executor):io.reactivex.Scheduler" resolve="from" />
+            <node concept="10M0yZ" id="19wqdqO45Or" role="37wK5m">
+              <ref role="1PxDUh" to="e5vs:~PooledThreadExecutor" resolve="PooledThreadExecutor" />
+              <ref role="3cqZAo" to="e5vs:~PooledThreadExecutor.INSTANCE" resolve="INSTANCE" />
+            </node>
+          </node>
+        </node>
+      </node>
+      <node concept="3uibUv" id="19wqdqO45DQ" role="3clF45">
+        <ref role="3uigEE" to="unkn:~Scheduler" resolve="Scheduler" />
+      </node>
+      <node concept="3Tm1VV" id="19wqdqO45zk" role="1B3o_S" />
+    </node>
+    <node concept="2tJIrI" id="19wqdqO45t$" role="jymVt" />
     <node concept="2YIFZL" id="3KwBCAA_erO" role="jymVt">
-      <property role="TrG5h" value="single" />
+      <property role="TrG5h" value="blocking" />
       <node concept="3uibUv" id="3KwBCAA_erP" role="3clF45">
         <ref role="3uigEE" to="unkn:~Scheduler" resolve="Scheduler" />
       </node>
@@ -7777,9 +7809,13 @@
           <node concept="9aQIb" id="3KwBCAA_Uq7" role="9aQIa">
             <node concept="3clFbS" id="3KwBCAA_Uq8" role="9aQI4">
               <node concept="3cpWs6" id="3KwBCAA_Uq9" role="3cqZAp">
-                <node concept="2YIFZM" id="3KwBCAAAg4Y" role="3cqZAk">
-                  <ref role="37wK5l" to="m4y7:~Schedulers.single():io.reactivex.Scheduler" resolve="single" />
+                <node concept="2YIFZM" id="19wqdqO465D" role="3cqZAk">
                   <ref role="1Pybhc" to="m4y7:~Schedulers" resolve="Schedulers" />
+                  <ref role="37wK5l" to="m4y7:~Schedulers.from(java.util.concurrent.Executor):io.reactivex.Scheduler" resolve="from" />
+                  <node concept="10M0yZ" id="19wqdqO465E" role="37wK5m">
+                    <ref role="3cqZAo" to="e5vs:~PooledThreadExecutor.INSTANCE" resolve="INSTANCE" />
+                    <ref role="1PxDUh" to="e5vs:~PooledThreadExecutor" resolve="PooledThreadExecutor" />
+                  </node>
                 </node>
               </node>
             </node>