Because SHOpenPropSheetW() is modal, there is no way for us to keep COM
alive on the original thread until the dialog completes, so a cloned
data object is used instead so that the property sheet handlers may access
the object even after ShellExecute() has returned (this is only relevant
for callers like Taskmgr that does not initialize COM even though MSDN
says they should).
Addendum to afc130ff3f (PR #7571). CORE-19933
- Implement SHOpenPropSheetW.
- Reuse already opened propertysheets and format dialogs by finding the existing unique stub window.
- Default .lnk property dialog to the shortcut tab.
Whindmar Saksit