IDEA-122994 Expanding hints overlaps real content & artifacts (to remove artifacts on method lookup we should not use several handlers at the same time)

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

@@ -93,11 +93,10 @@ public class LookupImpl extends LightweightHint implements LookupEx, Disposable,
       super.processKeyEvent(e);
     }
 
-    ExpandableItemsHandler<Integer> myExtender = new CompletionExtender(this);
     @NotNull
     @Override
-    public ExpandableItemsHandler<Integer> getExpandableItemsHandler() {
-      return myExtender;
+    protected ExpandableItemsHandler<Integer> createExpandableItemsHandler() {
+      return new CompletionExtender(this);
     }
   };
   final LookupCellRenderer myCellRenderer;

platform/platform-api/src/com/intellij/ui/components/JBList.java

@@ -173,7 +173,7 @@ public class JBList extends JList implements ComponentWithEmptyText, ComponentWi
       }
     };
 
-    myExpandableItemsHandler = ExpandableItemsHandlerFactory.install(this);
+    myExpandableItemsHandler = createExpandableItemsHandler();
     setCellRenderer(new DefaultListCellRenderer());
   }
 
@@ -202,6 +202,11 @@ public class JBList extends JList implements ComponentWithEmptyText, ComponentWi
     return myExpandableItemsHandler;
   }
 
+  @NotNull
+  protected ExpandableItemsHandler<Integer> createExpandableItemsHandler() {
+    return ExpandableItemsHandlerFactory.install(this);
+  }
+
   @Override
   public void setExpandableItemsEnabled(boolean enabled) {
     myExpandableItemsHandler.setEnabled(enabled);