Theming issues noted while porting Weather applet

[Kai Uwe Broulik]

> wel,, it should only use system color palettes, at least, there should be no 
combobox in the applet itself only in the config dialog and there the system 
theme/colors should be used?
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Yes but this is utterly broken like so many things in QQC. The ComboBox popup background is always white. The text follows theme colors, however, so it can end up gray on white if you're using dark application color scheme. This is a Qt bug and I have not idea how to fix it or at least workaround it.