Created attachment 110079 [details]
open system settings > workspace theme > look and feel
"Get new looks..." button continues using previous theme after I change from breeze dark to breeze or vice-versa. Reopen "Look and feel" kcm fixes the bug.
Ny screenshot taken on Arch Linux running plasma 5.12 beta shows the button after I changed from breeze to breeze dark.
Bug in QtQuick Controls 1 and likely to never be fixed (unless we move to QQC2 with desktop style where we have control over the stack and can actually fix things). I'll have a brief look tomorrow but when I cannot find a straight-forward solution (which I doubt) then I'll close this as upstream.
We'll need to move to QQC2 eventually anyway because of the text bug that's visible in the screenshot.
Git commit 900a334e72a7f334361fe8857d9a1144fdf52f46 by Kai Uwe Broulik.
Committed on 26/01/2018 at 14:53.
Pushed by broulik into branch 'Plasma/5.12'.
[Look and feel KCM] Destroy and recreate GHNS button when palette changes
Differential Revision: https://phabricator.kde.org/D10067
M +18 -5 kcms/lookandfeel/package/contents/ui/main.qml