[Bug] Tabs in sidebar are hidden after exiting some fullscreen videos

[BrontoRed]

Abstract

"Auto-hide sidebar when fullscreen #1548" snippet hides open tabs in sidebar after exiting fullscreen videos. Tabs in sidebar are shown again after hiding and opening sidebar.
Not all fullscreen videos trigger this issue.

Steps to reproduce

1. Start Firefox with clean profile.
2. Install TST.
3. Enable userChrome.css and "Auto-hide sidebar when fullscreen" snippet as described here and here and restart Firefox
4. Open link 1, link 2 and link 3, so that you have 3 tabs
5. Go to fullscreen video (double left click on video or press fullscreen button in player, but not with F11) in one of the pages above and then back to normal page view

Expected result

All open tabs in TST are visible in sidebar

Actual result

All open tabs in TST are hidden. Double tap F1 (or toolbar icon of TST) to restore tabs.

Environment

• Platform (OS): Windows 10 Pro 22H2
• Version of Firefox: 119.0
• Version (or revision) of Tree Style Tab: 3.9.17 (2023.9.8)