To reproduce this bug, try this:

1. Group select a section of your timeline.
2. The "Modify This Effect" Dialog box will appear.
3. Press CANCEL.

After you cancel this dialog box it will no longer appear. Restarting HLS will fix the problem. If you actually modify the effects and press OKAY, the dialog will continue to appear. The problem only happens if you CANCEL the dialog box.

-=Steve