FF 4.0b9: App Tabs disappear

[pfarmer821]

In FF 4.0b9 (Windows 32bit), App Tabs sometimes disappear when you close a tab. This happens for me under the following conditions:

1. The Tab Bar is positioned on the left side.
2. The skin of the Tab Bar is set to "Default (specified by the theme)".

If I set the skin of the Tab Bar to something else (for example, to "Mixed"), this is no longer a problem.

Opening and closing a Sidebar makes the App Tabs reappear. Restoring Down or Maximizing the Firefox window also makes the App Tabs reappear.

This was not a problem with FF 4.0b8. Maybe something has changed in the Default Theme to cause this behavior.

[piroor]

I tested on Minefield 4.0b10pre 20110121 on Windows Vista with TST HEAD, but I couldn't reproduce the problem. Could you test with the latest nightly of mozilla-central with the next release of TST?

[pfarmer821]

This issue can be closed. The problem is not present with FF 4.0b10 (Win 32bit), TST 0.11.2011012302, and Windows 7.

Cheers --