Created attachment 103898 [details] The yellow frame is shown. After the upgrade to 5.8.5 it happened. 1366/768. All widgets are checkboxes. http://i90.fastpic.ru/big/2017/0208/73/a4a452915b816507c5753e18b2353973.png
What Plasma theme are you using?
Simple Glass. But I reinstall the system, and such a problem on the same theme is gone.
Thanks for reporting back! Closing this bug report then.
Created attachment 106369 [details] Broken checkboxes in network popover; Correctly displayed in plasmathemeexplorer Checkboxes are broken in Plasma with a theme the worked just fine previously. plasmathemeexplorer displays them correctly after two tries.
I'm having the same (or a very similar) problem with 5.34 and I've had it for months (perhaps since 5.32), with a theme that worked perfectly for years (github.com/obnosim/velours) and which I have not changed significantly around the time or since the problem happened. See the attachment. You might also notice that the airplane icon is invisible (it seemed related for some reason; it happened at the same time and fiddling with the checkboxes makes it come back but with weird dimensions). plasmathemeexplorer displays checkboxes correctly (as seen in the attachment too) but only if I select my theme in it, then select another one, then select mine again (it's reproducible). It seems it needs two runs to get the metrics right (and even then it's borked, as the darker checked area was previously crisp and now it's blurry at best). openSUSE Tumbleweed x86_64 I remember the bug being there when I was running Qt 5.7, Plasma 5.9 and Frameworks 5.33. It's still there with Qt 5.9, Plasma 5.10.2 and Frameworks 5.34.