[COMCTL32]: comctl32/propsheet: Diverse UI fixes:
- Draw static text elements with a transparent background, so that they acquire the correct background color of the wizard window.
- Modify the check for the header bitmap, as the header's hbmHeader is initialized also if the flag PSH_HEADER but not PSH_USEHBMHEADER is set (see function PROPSHEET_LoadWizardBitmaps).
- Add a check for header's hbmWatermark so that the watermark is drawn only when a valid bitmap handle is present.
- Fix a copy-pasta error when drawing the header's subtitle.
CORE-12912 #comment Patch for the wizard visual problem sent upstream.
CORE-12823
svn path=/trunk/; revision=74136