Activating Commit Editor takes too long

1. Reset all unstaged changes in Creator's git repository
2. Open a file from the repository.
3. Change something in that file.
4. Select "Tools" -> "Git" -> "Local Repository" -> "Diff" from the menu.
   The Diff Editor shows up.
5. Press Ctrl+W.
   The Diff Editor closes immediately. This is how it should be.
6. Select "Tools" -> "Git" -> "Local Repository" -> "Commit..." from the menu.
7. In the Files section, select the changed file and click "Diff Selected Files".
   The Diff Editor shows up again.
8. Press Ctrl+W.
   It takes some seconds before the Diff Editor is being closed.

The Diff Editor should react immediately, no matter from where it was being opened.