Simon Urli So, the reason is that, when you added the UIXP for docextra tabs, you put it outside of the #if (!$docextra)## condition of https://github.com/xwiki/xwiki-platform/blob/62bd4d950e2c455c066c3612f448db59155fa6fe/xwiki-platform-core/xwiki-platform-flamingo/xwiki-platform-flamingo-skin/xwiki-platform-flamingo-skin-resources/src/main/resources/flamingo/docextra.vm#L31
See https://github.com/xwiki/xwiki-platform/commit/369f28408d508cecb81f00fa7e76c63bc66965df#diff-eaced188d8eb517d1b052672d6996ce8af5103fb0cb49bfe27ac460609eca2b5R71-R80
And the Main.AllDocs page is using #set ($docextras = []) to disable displaying the docextra tabs, thus the IF is not met and only UIX are injected... Since this is is a regression, I think we should move the injection inside the IF, WDYT?
Note that if on Main.AllDocs we use #set($displayDocExtra = false) (as indicated on https://www.xwiki.org/xwiki/bin/view/Documentation/DevGuide/Scripting/#HControllingPageTabs), it works fine. However since #set ($docextras = []) used to work, I still think we need to fix it.
