kdecoration: fix visual glitch in titlebar caption when it is updated near the edge
The geometry of the the title bar is not being correctly updated. The bug affects all C++-based window decorations (breeze, oxygen, even lightly) and can be observed when there isn't any title bar buttons to the left of the caption and the caption is changed (e.g. changing directories in dolphin), regardless of the alignment as long as the caption becomes close to the left edge. This makes sure that updateTitlebar sets the title bar's geometry in Decoration coordinates.
Please test and tell me what to do from here, as this is all very new for me. Also, I'm not sure whether I should make this into a one-liner.
Edited by Richard Shiue