on my laptop the minimum window height of the settings window is too high, I cannot get to the apply button :'< Reproducible: Always
Created attachment 93738 [details] screenshot
I can't reproduce this bug. My plasma version is 5.3.2. My qt version is 5.5.0. I'm using Arch Linux and my laptop is Asus K50IN. Screenshot: http://www.dodaj.rs/f/3e/SL/4DN6mBOt/slika4.png
Move your panel to the bottom ;)
Yup , when i changed my panel to the buttom, this bug is there :( sorry :) Even when you put window to maximize state ,still it wont fit to the screen and you can't see apply button. Confirmed.
I'm having this bug too on Plasma 5.5.3 Qt 5.5.1 I can still confirm the dialog box using the TAB key but it's a bit annoying. I can't resize it to a lower height too, and trying to move the window up it kinda "hit" the top margin on the screen and won't go higher.
Fixed with commit 7fd0f8ba2e2bcaad48d90104b70c9dd96c0b1138 by Olivier CHURLAUD to branch 1.6. see https://git.reviewboard.kde.org/r/128467