diff --git a/glsp-client/tasklist-glsp/src/model.ts b/glsp-client/tasklist-glsp/src/model.ts
index 0def81f0835827dc30961f6b6eb32380ad2789ee..09787fde8d8c3dbd77e4d688c24c7bf43ef87bf1 100644
--- a/glsp-client/tasklist-glsp/src/model.ts
+++ b/glsp-client/tasklist-glsp/src/model.ts
@@ -184,6 +184,16 @@ export function isPlace(element: GModelElement): boolean {
     return element.type === PNMLModelTypes.PLACE;
 }
 
+
+export function isRefTransition(element: GModelElement): boolean {
+    return element.type === PNMLModelTypes.REF_TRANSITION;
+}
+
+export function isRefPlace(element:GModelElement): boolean {
+    return element.type === PNMLModelTypes.REF_PLACE;
+}
+
+
 export interface HasArgs {
     args: any;
 }
diff --git a/glsp-client/tasklist-glsp/src/views.tsx b/glsp-client/tasklist-glsp/src/views.tsx
index 6a48c5a67d9b153d9f4e02d3e0e32bc84abf72b2..d102d619362b66d38117617bb9f070bbe4b313e2 100644
--- a/glsp-client/tasklist-glsp/src/views.tsx
+++ b/glsp-client/tasklist-glsp/src/views.tsx
@@ -45,6 +45,9 @@ export class DirectedEdgeView extends PolylineEdgeViewWithGapsOnIntersections {
         const additionals = super.renderAdditionals(edge, segments, context);
         const p1 = segments[segments.length - 2];
         const p2 = segments[segments.length - 1];
+
+        // edge.parent.move(edge, edge.parent.children.length - 1);
+
         const arrow = (
             <path
                 class-sprotty-edge={true}
diff --git a/glsp-client/tasklist-theia/src/browser/diagram/edit-input-signals-context-menu.ts b/glsp-client/tasklist-theia/src/browser/diagram/edit-input-signals-context-menu.ts
index e5bbb7a1b93ab533e4345b7b8607d808211ec362..81393267ceeef557cbd4707ed4960a35321147bd 100644
--- a/glsp-client/tasklist-theia/src/browser/diagram/edit-input-signals-context-menu.ts
+++ b/glsp-client/tasklist-theia/src/browser/diagram/edit-input-signals-context-menu.ts
@@ -18,7 +18,7 @@ import { GLSPCommandHandler, GLSPContextMenu } from '@eclipse-glsp/theia-integra
 import { CommandContribution, CommandRegistry, MenuContribution, MenuModelRegistry } from '@theia/core';
 import { ApplicationShell } from '@theia/core/lib/browser';
 import { inject, injectable } from 'inversify';
-import { isTransition, EditInputSignalMenu } from 'tasklist-glsp';
+import { isTransition, EditInputSignalMenu} from 'tasklist-glsp';
 
 export namespace EditInputSignalsMenuCommand {
     export const EDIT_INPUT_SIGNALS_MENU = 'edit-input-signals-menu-command';
@@ -37,7 +37,8 @@ export class EditInputSignalsMenuCommandContribution implements CommandContribut
                         visible: true
                     })
                 ],
-                isEnabled: context => !context.isReadonly && context.selectedElements.filter(isTransition).length === 1
+                isEnabled: context => !context.isReadonly && context.selectedElements.filter(isTransition).length === 1,
+                isVisible: context => !context.isReadonly && context.selectedElements.filter(isTransition).length === 1
             })
         );
     }
diff --git a/glsp-client/tasklist-theia/src/browser/diagram/reset-markings-context-menu.ts b/glsp-client/tasklist-theia/src/browser/diagram/reset-markings-context-menu.ts
index 2f00eba3a132f57f69016a3e3e82553211c9375f..c00b62a39596627401beb2dd0e7e4831e3e186cc 100644
--- a/glsp-client/tasklist-theia/src/browser/diagram/reset-markings-context-menu.ts
+++ b/glsp-client/tasklist-theia/src/browser/diagram/reset-markings-context-menu.ts
@@ -17,7 +17,7 @@ import { GLSPCommandHandler, GLSPContextMenu } from '@eclipse-glsp/theia-integra
 import { CommandContribution, CommandRegistry, MenuContribution, MenuModelRegistry } from '@theia/core';
 import { ApplicationShell } from '@theia/core/lib/browser';
 import { inject, injectable } from 'inversify';
-import { isPlace, ResetMarkingsOperation } from 'tasklist-glsp';
+import { isPlace, ResetMarkingsOperation} from 'tasklist-glsp';
 
 export namespace ResetMarkingsCommand {
     export const RESET_MARKINGS = 'reset-markings-command';
@@ -31,7 +31,8 @@ export class ResetMarkingsCommandContribution implements CommandContribution {
             { id: ResetMarkingsCommand.RESET_MARKINGS, label: 'Reset Markings' },
             new GLSPCommandHandler(this.shell, {
                 actions: context => [ResetMarkingsOperation.create()],
-                isEnabled: context => !context.isReadonly && context.selectedElements.filter(isPlace).length === 1
+                isEnabled: context => !context.isReadonly && context.selectedElements.filter(isPlace).length === 1,
+                isVisible: context => !context.isReadonly && context.selectedElements.filter(isPlace).length === 1
             })
         );
     }
diff --git a/glsp-server/src/main/java/org/eclipse/glsp/example/javaemf/handler/DiNeROS/ElementCreation/CreateNodePageNodeHandler.java b/glsp-server/src/main/java/org/eclipse/glsp/example/javaemf/handler/DiNeROS/ElementCreation/CreateNodePageNodeHandler.java
index d17629187cc2798a11f40a8aefa9a279f1e1a8ba..ace87223b633d40350b52fa5509deb9cb5d997e8 100644
--- a/glsp-server/src/main/java/org/eclipse/glsp/example/javaemf/handler/DiNeROS/ElementCreation/CreateNodePageNodeHandler.java
+++ b/glsp-server/src/main/java/org/eclipse/glsp/example/javaemf/handler/DiNeROS/ElementCreation/CreateNodePageNodeHandler.java
@@ -54,6 +54,34 @@ public class CreateNodePageNodeHandler extends CreatePageHandler
         return Optional.of(pageCommand);
     }
 
+    @Override
+    protected EObject getParentElement(final GModelElement container)
+    {
+        // prevent node page as root page (should be normal page, not a node)
+        if(container.getType().equals(PNMLModelTypes.GRAPH))
+            throw new IllegalCallerException("Node Page must be placed inside a Page.");
+        
+        //only basic page my be container for node page
+        if(!container.getType().equals(PNMLModelTypes.PAGE_NODE))
+            throw new IllegalCallerException("Node Page should only be contained inside a (basic) Page.");
+
+        // check if the new node page would be nested inside an existing node page (forbidden)
+        GModelElement temp = container;
+        while (temp != null)
+        {
+            String type = temp.getType();
+
+            if(type.equals(PNMLModelTypes.GRAPH)) 
+                break;
+
+            if(type.equals(PNMLModelTypes.NODE_PAGE_NODE))
+                throw new IllegalCallerException("Node Pages may not in any way contain a Node Page.");
+            
+            temp = temp.getParent();
+        }
+        return modelState.getIndex().getEObject(container.getId()).orElseThrow();
+    }
+
     protected ToolInfoPage createNodePageToolInfo (Page newPage)
     {
         ToolInfoPage toolSpecifics = PtnetFactory.eINSTANCE.createToolInfoPage();
diff --git a/glsp-server/src/main/java/org/eclipse/glsp/example/javaemf/handler/NodeCreation/CreatePageHandler.java b/glsp-server/src/main/java/org/eclipse/glsp/example/javaemf/handler/NodeCreation/CreatePageHandler.java
index 87514af3cb5a756bbaa89a5ce4e251e48c6955c5..81750db496b3dc3a901e5e5567bfa2f650fb4466 100644
--- a/glsp-server/src/main/java/org/eclipse/glsp/example/javaemf/handler/NodeCreation/CreatePageHandler.java
+++ b/glsp-server/src/main/java/org/eclipse/glsp/example/javaemf/handler/NodeCreation/CreatePageHandler.java
@@ -63,25 +63,35 @@ public class CreatePageHandler extends AbstractCreateNodeHandler<CreateNodeOpera
         return Optional.of(pageCommand);
     }
 
-    protected EObject getParentElement(final GModelElement container) {
-        if(container.getType().equals(PNMLModelTypes.PAGE_NODE)){ //page is subpage of other page
+    protected EObject getParentElement(final GModelElement container) 
+    {
+        String type = container.getType();
+
+        //page is subpage of other page or node page
+        if(type.equals(PNMLModelTypes.PAGE_NODE) || type.equals(PNMLModelTypes.NODE_PAGE_NODE))
             return modelState.getIndex().getEObject(container.getId()).orElseThrow();
-        } else if(container.getType().equals(PNMLModelTypes.GRAPH)){ //page is top level page
+
+        //page is top level page
+        if(type.equals(PNMLModelTypes.GRAPH))
             return modelState.getSemanticModel(pnml.class).orElseThrow()
                 .getNet().stream().findFirst().orElseThrow();
-        } else {
-            throw new IllegalArgumentException("Page must be placed in graph or other page.");
-        }
+                    
+        throw new IllegalArgumentException("Page must be placed in graph or other page.");
     }
 
-    protected EReference getRelationshipLiteral(final GModelElement container) {
-        if(container.getType().equals(PNMLModelTypes.PAGE_NODE)){ //page is subpage of other page
+    protected EReference getRelationshipLiteral(final GModelElement container) 
+    {
+        String type = container.getType();
+
+        //page is subpage of other page or node page
+        if(type.equals(PNMLModelTypes.PAGE_NODE) || type.equals(PNMLModelTypes.NODE_PAGE_NODE))
             return PtnetPackage.Literals.PAGE__PAGE;
-        } else if(container.getType().equals(PNMLModelTypes.GRAPH)){ //page is top level page
+        
+        //page is top level page
+        if(type.equals(PNMLModelTypes.GRAPH))
             return PtnetPackage.Literals.PETRI_NET__PAGE;
-        } else {
-            throw new IllegalArgumentException("Page must be placed in graph or other page.");
-        }
+
+        throw new IllegalArgumentException("Page must be placed in graph or other page.");
     }
 
     protected void denySecondRootPage(final GModelElement container)