4.2.11

• Custom tabs for grouping (ext+treestyletab:group) are available again on Firefox 150+ which never supports injecting of scripts to addon-hosted contents due to the bug 2011234. See #2356 in Sidebery for more details of affections of the bug.
• Fix wrong order of header and counter items for collapsed native tab groups after native groups are moved. (regression on 4.2.10)
• Stabilize tree restorations based on tree information stored to each tab (by tkng, thanks!)
• Don't leave phantom group and collapsed members counter after a collapsed native group is closed.
• Keep tree structure on detaching all children on some situations (including #3858 by tkng, thanks!)
• Suppress confirmation about closing multiple tabs if the number of closing tabs are smaller than the threashold 25 (same to the default value of browser.sessionstore.max_tabs_undo. If you changed it, please synchronize the threashold to the value of the option) like Firefox does, even if the confirmation is enabled. (by tkng, thanks!)
• Many performance improvements with optimizations and fixed leaks (#3854, #3865, #3857, #3870, #3872 and #3876 by tkng. Thanks!)
• Many cleanup of codes for future maintainability (#3853, #3855, #3856, #3859, #3860, #3862, #3863, #3864 and #3866 by tkng. Thanks!)
• Reduce dead codes around custom event handling and needless exports, for better maintainability.