There is no problem with the content display of each tab, but the tab bar is completely buggy.
If you open 5 or more tabs and browse tabs after the 5, the first 4 tab bars will be completely blacked out, and you don't even know how many tabs you have.
If you click on the place where the tab title probably exists, the tab is displayed as if the partial display of the tab bar has been restored.
There is no problem with content display. But because it is unclear what tab is open, the browsing experience is at its lowest.
If you switch to the tab after the 5th, the first 4 will return to the blackout state again.
Of course, it is the latest software configuration at the moment. There is no shortage of memory at 24GB.
I recently started developing a Safari extension with AppExtension, but is that due to it?