Contrast bug: KGlobalSettings::contrast() returns different default value than KGlobalSettings::contrastF(). Oxygen uses contrastF() while KDE color control module uses contrast(), so when the user first uses color settings, contrast appears to change.

Plasma popup bug: Right-aligned popups are one pixel away from right edge of the screen and top-aligned popups (when panel is on top) are one pixel inside panel. This is because the bug in QRect, where right() and bottom() value return value that is less than the true value by one. This is a feature-bug that Qt developers aren't going to fix because of compatiability reasons. My patch just applies + 1 compensation to all expressions that use QRect::right() and QRect::bottom().