http://www.jetbrains.net/jira/browse/IDEADEV-440 fixed

source/com/intellij/ide/todo/CurrentFileTodosPanel.java

@@ -47,6 +47,8 @@ abstract class CurrentFileTodosPanel extends TodoPanel{
       return;
     }
 
+    if (file != null && getSelectedFile() == file.getVirtualFile()) return;
+
     PsiDocumentManager.getInstance(myProject).commitAllDocuments();
     CurrentFileTodosTreeBuilder builder = (CurrentFileTodosTreeBuilder)myTodoTreeBuilder;
     builder.setFile(file);

source/com/intellij/ide/todo/TodoPanel.java

@@ -219,7 +219,7 @@ abstract class TodoPanel extends JPanel implements OccurenceNavigator, DataProvi
   /**
    * @return list of all selected virtual files.
    */
-  private VirtualFile getSelectedFile() {
+  protected VirtualFile getSelectedFile() {
     TreePath path = myTree.getSelectionPath();
     if (path == null) {
       return null;