basically now my model controls text color through Qt::ForegroundRole regardless of the application's CSS.
I feel like it's the wrong place to put theming, but it works for me at the moment.
Well... until we decide to have different themes :-°
That's definitely a bug. There seems to be a bug report about it QTBUG-15203, but it has been closed due to Qt4 EOL. Since it's still valid please report it for Qt5.
As for a workaround I'm afraid you will need to paint the tabs yourself. If you don't wan't to subclass and override paintEvent you can install an event filter and handle the painting there. Other that that I can't think of any other solution, apart maybe from adding some spaces to the front of the strings :P (just kidding, don't do it).
@Chris-Kawa I just have to say this is hilarious and spot on. I did this same thing in wxWidgets a couple years ago and this was my experience verbatim. In the end I went on to use the same basic technique that is described here: https://github.com/deimos1877/BorderlessWindow. Thanks for making me feel less stupid.
As suggested in that link before, em and rem create perfectly scalable sizes. Don't let the name and description fool you: although the size refers to the size of the M character, they can be applied to width, height and any other CSS property as well.
As for items being QObject derived classes, rather not. The various QXXXItem classes must be as lightweight as possible since there can be several thousands of them and QObject has a cost and constraints. Except maybe in a few corner cases there would be no real benefit to have it there for the common usage.
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