It seems that the Aurorae engine in Plasma 5 is showing hover button variants for deactivated buttons. This is easy to see with any Aurorae-based window decoration that has visually distinct (or invisible/missing) deactivated maximize button, such as Simple Glass. Reproducible: Always Steps to Reproduce: 1. Go to System Settings / Application Style / Window Decorations 2. Install an appropriate Aurorae-based window decoration theme, such as Simple Glass 3. Select the theme and Apply 4. Open kcalc (Scientific Calculator) 5. Note that kcalc's maximize button is deactivated/absent 6. Mouse over the deactivated/absent maximize button and note that the active/inactive hover effect is shown Actual Results: Maximize button is (properly) invisible, but active/inactive hover effect is show when button is moused over. Expected Results: No hover effect; deactivated/invisible button shouldn't change.
Not reproducibly here, side-effect of https://git.reviewboard.kde.org/r/125917/ ?
Wow, I can actually reproduce this one on Plasma from master, but only with specific themes. Breeze and SierraBreezeEnhanced do not show nor highlight the maximize button on hover. Infinity-Aurorae and FormaN show and highlight it. Plastik and Nordic show but don't highlight it.