2021-11 Ruleset: Small sidebar buttons no longer have tooltips
The small sidebar buttons (Combat Tracker, Party Sheet, Calendar, etc.) don't appear to have tooltips any longer, which may make it harder for newer users to identify them.
On a separate note, the collapsible sidebar categories are a really nice improvement. Have you considered changing any of the small buttons at the top (e.g. Combat Tracker) to be the same style as the other buttons? For example, Options and Colors could move to a "Settings" category.
5E ruleset v2021-11-15
FGU v4.1.10