Dolphin is using some glossy style for space usage indicators (retrofitted progress bars?); Make them use the system style verbatim.
Dolphin foodbar in Plasma 5.4 and in the property section (folder -> property) I think this is solved or do you mean something different?
Ah, I'm not on 5.4 yet, but that looks like all the correct stuff.
I saw the bug report and yesterday on KaOS 15.08 Plasma 5.4. Should work now or.
sorry don't saw the resolved icon. but phab is cool