The flag (#overlay-scrollbars) doesn't fix the scrollbar. It just changes its behavor.
No scrolling no visible scrollbar (so can't drag)
While scrolling the narrow bar appears
On hover the same ugly scrollbar appears.
Btw, I reported the bug a week ago but anyway it leaked to Stable. https://forums.opera.com/post/401337
>Fixes for Easy Setup UI, including layout gaps and visual inconsistencies
EasySetup still closes while trying to grab and drag its scrollbar if the cursor is on the 1px content border (the bug persists since the autumn 2025 since 122 version > https://forums.opera.com/post/394135).
And despite of being reported the 'force dark page' switch doesn't remember its state after themes switching and theme tile's menus don't reset and stay open on hover in reopened EasySetup >https://forums.opera.com/post/398589
And in Settings there's still a glitch with dark mode's force dark page switch (was reported multiple times as well).