When using VisualEditor in Vector, I've been irritated by the strong border of the selected Vector tabs and VE's toolbar, which is counter-intuitive to “what's currently selected” connecting white space.
The blue separators were introduced in https://gerrit.wikimedia.org/r/#/c/210314/, my understanding is, the reason behind the change were the horizontal toolbar separators in VE toolbar, which would end in nil.
Before:
@Pginer-WMF My proposal would be to slightly reduce contrast of “border” by using #e1f1fc (decrease to 33% opacity of normal border) as color
We can't use things like dashed or dotted borders as those would
No border is not a possibility either.
Having border color reduced seems like the only workable compromise between various options to me.
A media query at least for Edit tab (above 1170px) could be an additional, but from a maintenance aspect not too aspiring solution.
Change 372200 had a related patch set uploaded (by VolkerE; owner: VolkerE):
[mediawiki/extensions/VisualEditor@master] Decrease border contrast on selected Vector tabs
Seems a good compromise to keep the active tabs more connected with the content they represent, while still keeping the toolbar consistent as one element.
Change 372200 merged by jenkins-bot:
[mediawiki/extensions/VisualEditor@master] Decrease border contrast on selected Vector tabs