diff --git a/plugins/org.locationtech.udig.project.ui/src/org/locationtech/udig/project/ui/ApplicationGIS.java b/plugins/org.locationtech.udig.project.ui/src/org/locationtech/udig/project/ui/ApplicationGIS.java
index 2558c4fa62..64293c7c07 100644
--- a/plugins/org.locationtech.udig.project.ui/src/org/locationtech/udig/project/ui/ApplicationGIS.java
+++ b/plugins/org.locationtech.udig.project.ui/src/org/locationtech/udig/project/ui/ApplicationGIS.java
@@ -802,7 +802,9 @@ public void run(IProgressMonitor monitor)
                 RendererCreator decisive = new RendererCreatorImpl();
                 decisive.setContext(tools);
 
-                decisive.getLayers().addAll(layersToRender);
+                synchronized (decisive.getLayers()) {
+                    decisive.getLayers().addAll(layersToRender);
+                }
 
                 SortedSet<RenderContext> sortedContexts = new TreeSet<RenderContext>(
                         decisive.getConfiguration());
diff --git a/plugins/org.locationtech.udig.project/src/org/locationtech/udig/project/internal/render/impl/RendererCreatorImpl.java b/plugins/org.locationtech.udig.project/src/org/locationtech/udig/project/internal/render/impl/RendererCreatorImpl.java
index cc93e2edd1..3ceff13b39 100644
--- a/plugins/org.locationtech.udig.project/src/org/locationtech/udig/project/internal/render/impl/RendererCreatorImpl.java
+++ b/plugins/org.locationtech.udig.project/src/org/locationtech/udig/project/internal/render/impl/RendererCreatorImpl.java
@@ -499,12 +499,14 @@ public SelectionLayer findSelectionLayer( ILayer targetLayer ) {
         } catch (IOException e) {
             return null;
         }
-        for( Layer layer : getLayers() )
-            if (layer instanceof SelectionLayer)
-                if (((SelectionLayer) layer).getWrappedLayer() == targetLayer)
-                    return (SelectionLayer) layer;
+        synchronized (getLayers()) {
+            for (Layer layer : getLayers())
+                if (layer instanceof SelectionLayer)
+                    if (((SelectionLayer) layer).getWrappedLayer() == targetLayer)
+                        return (SelectionLayer) layer;
 
-        return null;
+            return null;
+        }
     }
 
     /**