EA-37161

plugins/ui-designer/ui-designer-new/src/com/intellij/designer/designSurface/DesignerEditorPanel.java

@@ -363,7 +363,7 @@ public abstract class DesignerEditorPanel extends JPanel implements DataProvider
   }
 
   public final void showError(@NotNull String message, @NotNull Throwable e) {
-    if (getProject().isDisposed()) {
+    if (isProjectClosed()) {
       return;
     }
 
@@ -540,6 +540,10 @@ public abstract class DesignerEditorPanel extends JPanel implements DataProvider
     return myProject;
   }
 
+  public final boolean isProjectClosed() {
+    return myProject.isDisposed() || !myProject.isOpen();
+  }
+
   public EditableArea getSurfaceArea() {
     return mySurfaceArea;
   }

plugins/ui-designer/ui-designer-new/src/com/intellij/designer/designSurface/ExternalPSIChangeListener.java

@@ -102,7 +102,7 @@ public class ExternalPSIChangeListener extends PsiTreeChangeAdapter {
     myAlarm.addRequest(new Runnable() {
       @Override
       public void run() {
-        if (myRunState && myInitialize && !myDesigner.getProject().isDisposed()) {
+        if (myRunState && myInitialize && !myDesigner.isProjectClosed()) {
           runnable.run();
         }
       }