diff --git a/reactor/Core/src/jetbrains/mps/logic/reactor/core/internal/MatchHistory.kt b/reactor/Core/src/jetbrains/mps/logic/reactor/core/internal/MatchHistory.kt
index 586b56e9..cd9b94e3 100644
--- a/reactor/Core/src/jetbrains/mps/logic/reactor/core/internal/MatchHistory.kt
+++ b/reactor/Core/src/jetbrains/mps/logic/reactor/core/internal/MatchHistory.kt
@@ -19,8 +19,11 @@ package jetbrains.mps.logic.reactor.core.internal
 import gnu.trove.set.TIntSet
 import gnu.trove.set.hash.TIntHashSet
 import jetbrains.mps.logic.reactor.core.Occurrence
+import jetbrains.mps.logic.reactor.evaluation.ConstraintOccurrence
 import jetbrains.mps.logic.reactor.evaluation.RuleMatch
 import jetbrains.mps.logic.reactor.evaluation.StoreView
+import jetbrains.mps.logic.reactor.program.ConstraintSymbol
+import jetbrains.mps.logic.reactor.util.Id
 import java.util.*
 import kotlin.collections.ArrayList
 
@@ -28,6 +31,7 @@ import kotlin.collections.ArrayList
 interface MatchHistory {
     data class View(val chunks: List<Chunk>, val nextChunkId: Int)
 
+
     data class Chunk(val match: RuleMatch, val id: Int, val justifications: TIntSet) {
         data class Entry(val occ: Occurrence, val isDiscarded: Boolean = false) {
             override fun toString() = (if (isDiscarded) '-' else '+') + occ.toString()
@@ -106,7 +110,15 @@ internal class MatchHistoryImpl(val state: ProcessingStateImpl, view: MatchHisto
     }
 
     // TODO:
-    override fun storeView(): StoreView = state.storeView()
+    override fun storeView(): StoreView = StoreViewImpl(allOccurrences())
+
+    private fun allOccurrences(): Sequence<Occurrence> {
+        val set = HashSet<Id<Occurrence>>()
+        hist.flatMap { it.occurrences } .forEach {
+            if (it.isDiscarded) set.add(Id(it.occ)) else set.remove(Id(it.occ))
+        }
+        return set.map { it.wrapped }.asSequence()
+    }
 
     override fun view() = MatchHistory.View(ArrayList(hist), nextChunkId)
 
@@ -192,6 +204,22 @@ internal class MatchHistoryImpl(val state: ProcessingStateImpl, view: MatchHisto
 
     // fixme: does belong to here?
 //    fun resetOrder() { order = hist.mapToIndex() }
+
+
+    private class StoreViewImpl(occurrences: Sequence<Occurrence>) : StoreView {
+
+        val allOccurrences = occurrences.toSet()
+
+        val allSymbols = allOccurrences.map { co -> co.constraint().symbol() }.toSet()
+
+        override fun constraintSymbols(): Iterable<ConstraintSymbol> = allSymbols
+
+        override fun allOccurrences(): Iterable<ConstraintOccurrence> = allOccurrences
+
+        override fun occurrences(symbol: ConstraintSymbol): Iterable<ConstraintOccurrence> =
+            allOccurrences.filter { co -> co.constraint().symbol() == symbol }.toSet()
+
+    }
 }
 
 private fun RuleMatch.headJustifications(): TIntSet {
diff --git a/reactor/Core/src/jetbrains/mps/logic/reactor/core/internal/ProcessingStateImpl.kt b/reactor/Core/src/jetbrains/mps/logic/reactor/core/internal/ProcessingStateImpl.kt
index af6f71a3..03bf3f35 100644
--- a/reactor/Core/src/jetbrains/mps/logic/reactor/core/internal/ProcessingStateImpl.kt
+++ b/reactor/Core/src/jetbrains/mps/logic/reactor/core/internal/ProcessingStateImpl.kt
@@ -106,35 +106,4 @@ internal class ProcessingStateImpl private constructor(val trace: EvaluationTrac
         // forward to the top frame
         currentFrame().parentUpdated(logical)
     }
-
-    fun storeView(): StoreView =
-        StoreViewImpl(allOccurrences())
-
-    private fun allOccurrences(): Sequence<Occurrence> {
-        val dit = stateFrames.descendingIterator()
-        val set = HashSet<Id<Occurrence>>()
-        while (dit.hasNext()) {
-            val stateFrame = dit.next()
-            stateFrame.allActivated().forEach { set.add(Id(it)) }
-            stateFrame.allDeactivated().forEach { set.remove(Id(it)) }
-        }
-        return set.map { it.wrapped }.asSequence()
-    }
-
-    private class StoreViewImpl(occurrences: Sequence<Occurrence>) : StoreView {
-
-        val allOccurrences = occurrences.toSet()
-
-        val allSymbols = allOccurrences.map { co -> co.constraint().symbol() }.toSet()
-
-        override fun constraintSymbols(): Iterable<ConstraintSymbol> = allSymbols
-
-        override fun allOccurrences(): Iterable<ConstraintOccurrence> = allOccurrences
-
-        override fun occurrences(symbol: ConstraintSymbol): Iterable<ConstraintOccurrence> =
-            allOccurrences.filter { co -> co.constraint().symbol() == symbol }.toSet()
-
-    }
-
-
 }
\ No newline at end of file
diff --git a/reactor/Core/src/jetbrains/mps/logic/reactor/core/internal/StateFrame.kt b/reactor/Core/src/jetbrains/mps/logic/reactor/core/internal/StateFrame.kt
index 1c861e4a..6a4d7232 100644
--- a/reactor/Core/src/jetbrains/mps/logic/reactor/core/internal/StateFrame.kt
+++ b/reactor/Core/src/jetbrains/mps/logic/reactor/core/internal/StateFrame.kt
@@ -45,10 +45,6 @@ internal class StateFrame private constructor(val state: ProcessingStateImpl) :
 
     private var observers: PersMap<Id<Logical<*>>, ConsList<LogicalObserver>> = Maps.of()
 
-    private val activatedOccurrences = ArrayList<Occurrence>(4)
-    
-    private val deactivatedOccurrences = ArrayList<Occurrence>(4)
-
     constructor(state: ProcessingStateImpl, dispatcher: Dispatcher) : this(state) {
         this.dispatchingFront = dispatcher.front()
     }
@@ -95,12 +91,6 @@ internal class StateFrame private constructor(val state: ProcessingStateImpl) :
         }
     }
 
-    fun allActivated() : Sequence<Occurrence> =
-        activatedOccurrences.asSequence()
-
-    fun allDeactivated() : Sequence<Occurrence> =
-        deactivatedOccurrences.asSequence()
-
     /**
      * Called to update the state with the currently active constraint occurrence.
      * Calls the controller to process matches (if any) that were triggered.
@@ -119,7 +109,6 @@ internal class StateFrame private constructor(val state: ProcessingStateImpl) :
                 state.trace.reactivate(active)
             }
 
-            activatedOccurrences += active
             this.dispatchingFront = dispatchingFront.expand(active)
 
             val outStatus = dispatchingFront.matches().toList().fold(inStatus) { status, match ->
@@ -167,7 +156,6 @@ internal class StateFrame private constructor(val state: ProcessingStateImpl) :
 
         match.forEachReplaced { occ ->
             this.dispatchingFront = dispatchingFront.contract(occ)
-            deactivatedOccurrences += occ
 
             occ.stored = false
             occ.terminate()