Our On-Screen Keyboard has a manifest and the buttons (the ones with BS_ICON styles) aren't rendered with the specific theme as it should be but instead it takes the classic theme.
The code relies on NM_CUSTOMDRAW notification, which is more intuitive and efficient than doing owner-drawn operations as NM_CUSTOMDRAW allows the controls to use styles whereas you cannot do it on owner-drawn controls.
CORE-15965
On-Screen Keyboard has a manifest which is used for visual styles. However, the common controls aren't initialized and as a general rule the controls have to be loaded in the application's handle instance.
On-Screen Keyboard provides a mechanism to launch the application only once, to avoid multiple entry point instances. Such mechanism is based upon mutex objects, although it could happen that the program may end up creating two or more mutexes (a race condition).
CORE-15877