Regression, scaling, the bottom right corner of the taskmgr CPU-power-meter is cropped

0.4.12-dev-824-gd57f7be gcc dbg linux official iso is affected (without having any font fixes applied locally)

Just open the taskmgr performance tab and watch the performance meter control.

Expected result
0.4.12-dev-8-g958ae44_ok.png ros taskmgr on ros looks fine.
It looks as fine as the taskmgr from ros 0.4.12-dev-824-gd57f7be executed in WinXP (which proves our taskmgr binary being correct)

Observed result
0.4.12-dev-824-gd57f7be_PowerMeterScalingIssue.png
0.4.12-dev-824-gd57f7be_PowerMeterScalingIssue.log

I guess it's some regression in scaling, because when the affected taskmgrs window is expanded vertically, the bottom right element is suddenly properly drawn again, see
0.4.12-dev-824-gd57f7be_PowerMeterScalingIssue.webm

We still need to find the guilty revision in between.