Inconsistent Tab Activity Flag

[dimitrik-fr]

Describe the bug

Having tab_activity_symbol option is very helpful to be alerted on time about any "activity" in tabs which are not currently under focus. However, it partially lacks of consistency. You may still have some activity in tab, but it'll not be reported on time.

To Reproduce

Steps to reproduce the issue:

1. first of all add tab_bar_min_tabs 1 and tab_activity_symbol * into your ketty.conf (whatever symbol you like, not particularly * ;-))
2. now start ketty
3. create second tab
4. start top in this second tab
5. switch back to the first tab and wait..
6. regardless that top is running in the second tab, there will still be no any activity mentioned for this tab
7. and only if you'll switch to another app and then back to ketty again (or click on tab bar on the first tab) -- then activity sign will finally appear ! ;-))
8. but wait, it's not all..
9. stay on the first tab, and now close it
10. ketty will automatically switch you to the second tab where top is running (becomes the first and single tab)
11. focus is now on this tab, but "activity sign" is still present in tab bar for this tab
12. now stop top
13. there is no more any activity, but "activity sign" is still here
14. clicking on tab in tab bar will not help ;-))
15. and only by switching from kitty to another app, and then back will disappear the "activity sign"

Expected behavior

The expected behavior would be to see "activity sign" in tab bar in given tab as soon as there is some activity. I hope the test case proposed above is self-explaining, but let me know if it's not so..

Rgds, -Dimitri