Dialogbox has been initialized just after creating the tab control
- handle the case when pszCaption specifies a resource instead of a string

- better parameter checking for shellfolder
- removed dead code from shv_bg_contextmenu

Internal structures are now really internal.

Matches Windoze behavior.

role a little, added policy data table.

mmioDescend offset and alignment issues).

function.

DROPEFFECT_NONE if the user cancelled the operation.

hInstance==NULL.