Hi, I can't reproduce this on Windows 7. I've tried:
1. Open the .capx. Tabs for Layout 1, Layout 2 and Event sheet 1 are open, and Event sheet 1 is displaying.
2. Click the Layout 1 tab.
3. Click the Event sheet 1 tab.
4. Middle click Layout 2 tab to close it.
I don't see any error. Am I doing something different to you?