diff --git a/com.incquerylabs.v4md/src/main/com/incquerylabs/v4md/V4MDPlugin.java b/com.incquerylabs.v4md/src/main/com/incquerylabs/v4md/V4MDPlugin.java
index cd388b9..6b86246 100644
--- a/com.incquerylabs.v4md/src/main/com/incquerylabs/v4md/V4MDPlugin.java
+++ b/com.incquerylabs.v4md/src/main/com/incquerylabs/v4md/V4MDPlugin.java
@@ -1,6 +1,7 @@
 package com.incquerylabs.v4md;
 
 import com.incquerylabs.v4md.expressions.BinaryVQLExpression;
+import com.incquerylabs.v4md.internal.IProjectChangedListener;
 import com.nomagic.ci.persistence.IProject;
 import com.nomagic.magicdraw.core.Application;
 import com.nomagic.magicdraw.core.Project;
@@ -11,8 +12,9 @@
 import com.nomagic.magicdraw.expressions.evaluation.ExpressionEvaluationConfigurator;
 
 public class V4MDPlugin extends com.nomagic.magicdraw.plugins.Plugin {
-	
+
 	private final class V4MDProjectListener extends ProjectEventListenerAdapter implements ProjectPartListener {
+		
 		@Override
 		public void projectOpened(Project project) {
 			ViatraQueryAdapter.getOrCreateAdapter(project);
@@ -22,29 +24,29 @@ public void projectOpened(Project project) {
 		public void projectPreClosed(Project project) {
 			ViatraQueryAdapter.disposeAdapter(project);
 		}
-
+		
 		@Override
 		public void projectPartLoaded(Project project, IProject storage) {
-			ViatraQueryAdapter.getAdapter(project).ifPresent(ViatraQueryAdapter::projectStructureUpdated);
+			IProjectChangedListener.MANAGER.notifyProjectListeners(project);
 		}
 
 		@Override
 		public void projectPartAttached(ModuleUsage usage) {
 			Project project = ProjectUtilities.getProject(usage.getUsed());
-			ViatraQueryAdapter.getAdapter(project).ifPresent(ViatraQueryAdapter::projectStructureUpdated);
+			IProjectChangedListener.MANAGER.notifyProjectListeners(project);
 		}
 
 		@Override
 		public void projectPartDetached(ModuleUsage usage) {
 			Project project = ProjectUtilities.getProject(usage.getUsed());
-			ViatraQueryAdapter.getAdapter(project).ifPresent(ViatraQueryAdapter::projectStructureUpdated);
+			IProjectChangedListener.MANAGER.notifyProjectListeners(project);
 			
 		}
 
 		@Override
 		public void projectPartRemoved(IProject project) {
 			Project modelProject = ProjectUtilities.getProject(project);
-			ViatraQueryAdapter.getAdapter(modelProject).ifPresent(ViatraQueryAdapter::projectStructureUpdated);
+			IProjectChangedListener.MANAGER.notifyProjectListeners(modelProject);
 		}
 	}
 
diff --git a/com.incquerylabs.v4md/src/main/com/incquerylabs/v4md/internal/IProjectChangedListener.java b/com.incquerylabs.v4md/src/main/com/incquerylabs/v4md/internal/IProjectChangedListener.java
new file mode 100644
index 0000000..80facf3
--- /dev/null
+++ b/com.incquerylabs.v4md/src/main/com/incquerylabs/v4md/internal/IProjectChangedListener.java
@@ -0,0 +1,33 @@
+package com.incquerylabs.v4md.internal;
+
+import com.google.common.collect.ArrayListMultimap;
+import com.nomagic.magicdraw.core.Project;
+
+public interface IProjectChangedListener {
+	void modelSetUpdated();
+	
+	public static final Manager MANAGER = new Manager();
+	
+	public class Manager {
+		ArrayListMultimap<Project, IProjectChangedListener> listenerMap = ArrayListMultimap.create();
+		
+		
+		private Manager() {
+			// Private constructor for singleton class
+		}
+
+		public void notifyProjectListeners(Project project) {
+			for (IProjectChangedListener listener : listenerMap.get(project)) {
+				listener.modelSetUpdated();
+			}
+		}
+		
+		public boolean addProjectChangeListener(Project project, IProjectChangedListener listener) {
+			return listenerMap.put(project, listener);
+		}
+		
+		public boolean removeProjectChangeListener(Project project, IProjectChangedListener listener) {
+			return listenerMap.remove(project, listener);
+		}
+	}
+}
\ No newline at end of file
diff --git a/com.incquerylabs.v4md/src/main/com/incquerylabs/v4md/internal/MagicDrawProjectEngineContext.java b/com.incquerylabs.v4md/src/main/com/incquerylabs/v4md/internal/MagicDrawProjectEngineContext.java
index 5d20880..25a4637 100644
--- a/com.incquerylabs.v4md/src/main/com/incquerylabs/v4md/internal/MagicDrawProjectEngineContext.java
+++ b/com.incquerylabs.v4md/src/main/com/incquerylabs/v4md/internal/MagicDrawProjectEngineContext.java
@@ -27,7 +27,6 @@
 import org.eclipse.viatra.query.runtime.matchers.context.IQueryRuntimeContext;
 
 import com.google.common.collect.Sets;
-import com.incquerylabs.v4md.internal.MagicDrawProjectScope.IProjectChangedListener;
 
 /**
  * Provides a specific engine context implementation for MagicDraw projects.
@@ -101,7 +100,7 @@ public void removeRoot(Notifier root) {
 	            return;
 
 	        // no veto by filters
-	        modelRoots.add(root);
+	        modelRoots.remove(root);
 	        // TODO contentAdapter.removeAdapter(root); removeAdapter is not visible here
 	        Method method;
 			try {
@@ -120,7 +119,7 @@ public MagicDrawProjectEngineContext(MagicDrawProjectScope scope, ViatraQueryEng
         this.engine = engine;
         this.logger = logger;
         this.taintListener = taintListener;
-        scope.addProjectChangeListener(scopeListener);
+        IProjectChangedListener.MANAGER.addProjectChangeListener(scope.getProject(), scopeListener);
     }
     
     /**
@@ -169,7 +168,7 @@ public void dispose() {
         if (runtimeContext != null) runtimeContext.dispose();
         if (navHelper != null) navHelper.dispose();
         
-        scope.removeProjectChangeListener(scopeListener);
+        IProjectChangedListener.MANAGER.removeProjectChangeListener(scope.getProject(), scopeListener);
         
         this.baseIndex = null;
         this.engine = null;
diff --git a/com.incquerylabs.v4md/src/main/com/incquerylabs/v4md/internal/MagicDrawProjectScope.java b/com.incquerylabs.v4md/src/main/com/incquerylabs/v4md/internal/MagicDrawProjectScope.java
index 153809d..5c2350c 100644
--- a/com.incquerylabs.v4md/src/main/com/incquerylabs/v4md/internal/MagicDrawProjectScope.java
+++ b/com.incquerylabs.v4md/src/main/com/incquerylabs/v4md/internal/MagicDrawProjectScope.java
@@ -33,9 +33,6 @@ public class MagicDrawProjectScope extends EMFScope {
 					&& ((EReference) reference).isContainment() && reference.getName().contains("_from_"))
 			.withStrictNotificationMode(false);
 	
-	public interface IProjectChangedListener {
-		void modelSetUpdated();
-	}
 	static Stream<? extends Notifier> getProjectModels(Project projectModel) {
 		return projectModel.getModels().stream();
 	}
@@ -60,14 +57,6 @@ protected IEngineContext createEngineContext(ViatraQueryEngine engine, IIndexing
 			Logger logger) {
 		return new MagicDrawProjectEngineContext(this, engine, errorListener, logger);
 	}
-
-	boolean addProjectChangeListener(IProjectChangedListener listener) {
-		return listeners.add(listener);
-	}
-	
-	boolean removeProjectChangeListener(IProjectChangedListener listener) {
-		return listeners.remove(listener);
-	}
 	
 	public void projectStructureUpdated() {
 		for (IProjectChangedListener listener : listeners) {