IDEA-142715 It's impossible to move multiple files by mouse between changelists or even select several files via Ctrl/Cmd+Click

platform/util/src/com/intellij/util/ui/tree/WideSelectionTreeUI.java

@@ -129,6 +129,12 @@ public class WideSelectionTreeUI extends BasicTreeUI {
     UIManager.put("Tree.repaintWholeRow", myOldRepaintAllRowValue);
   }
 
+  @Override
+  public void installUI(JComponent c) {
+    super.installUI(c);
+    tree.setDragEnabled(true);
+  }
+
   @Override
   protected void installKeyboardActions() {
     super.installKeyboardActions();