affected is current head r70739 & 0.4RC2
not affected is 0.3.17
steps to reproduce:
-disable & stop themesvc
-open a explorer file browser
-navigate into at least one subfolder in FS
as soon as you double-click the folder, the title bar/window position will jump up about 1 or 2 pixels
This does not happen when themesvc is enabled but without a theme selected.