Hello.

I'm writing some UI code which contains also an OK button and a Cancel button. The Breeze icons of these buttons are blurry. (I'm using a HiDPI screen at 150%.)

Now, I do not understand why the icons are blurry. The code is hand-written (no UI file) and contains a QDialogButtonBox with a QDialog-derived dialog. It does not explicitly request the icons (and, when choosing some other widget styles than Breeze, the might be no icon at all).

When I create a widget in Qt Designer, using a QDialogButtonBox, and doing a preview in Breeze style, they are not blurry. Once I compile this UI file, it gets blurry again.

Also, I’ve noticed that in KDE, a lot of application have these blurry OK and Cancel button icons, and a lot of applications have non-blurry icons (KSysGuard for examle). But I do not find the difference in the code. For example, the very same Qt Designer application itself, at Form→Form settings, has a dialog which has a non-blurry OK icon in Breeze style. When looking at the source code of the Qt Designer app, there is nothing special: It‘s just a UI file that makes use of a QDialogButtonBox.

So: What makes this difference? What am I overlooking?