Image Viewer Functions:
 Window Control
  Callbacks

DISPCONTAINERACTIONCALLBACK

DISPCONTAINERACTIVESUBCELLCHANGED

DISPCONTAINERANNOTATIONCALLBACK

DISPCONTAINERANNOTATIONCREATEDCALLBACK

DISPCONTAINERMOUSECALLBACK

DISPCONTAINERPAINTCALLBACK

DISPCONTAINERPOSTPAINTCALLBACK

DISPCONTAINERPREPAINTCALLBACK

DISPCONTAINERREGIONCALLBACK

DISPCONTAINERTAGCALLBACK