IDEA-203019/IDEA-148060: Completion doesn't work after switching window

platform/lang-impl/src/com/intellij/codeInsight/lookup/impl/LookupImpl.java

@@ -1096,6 +1096,11 @@ public class LookupImpl extends LightweightHint implements LookupEx, Disposable,
     return myAdComponent.getAdvertisements();
   }
 
+  @Override
+  protected void onPopupCancel() {
+    hide();
+  }
+
   @Override
   public void hide(){
     hideLookup(true);