there's some improvement here with that PR:

but .. not there yet.

to me that's this class (as seen from firefox devtools) that adds too much padding around the tab title:

.geOrchestra .nav > li > a {
  padding: 10px 15px;
}

but from my understanding thats a class from the mapstore css, not the extension css. or the padding should be set to less in the added class ?

im definitely not a css wizard, but changing the above class to set 2px 5px might not be pixel perfect, but it aligns more with the other tabs size..

Modified. Let me know if it's good for you.

thanks, i've retested it here and it looks great now !

one 'funny' thing i noted on the way, if you have 'selection 1' and 'selection 2' tabs, and close 'selection 1', it will .. 'rename' the 'selection 2' tab to 'selection 1'. But the tabs created from a search by plot dont change name and keep the commune name/insee code in their title, so i guess the tabs being renamed are... a minor UX inconsistency ?