I've created a non-rectangular Logoff and Shutdown dialog.

The area that should be transparent is 'magic pink'.

I was getting the effect that there was a rectangular area around my non-rectangular dialog that would NOT fade to gray.

I changed the "Shutdown/Logoff Screen mask (per pixel)

Now, NO part of the screen goes gray (and since the dialog is the same background colour as the desktop, it's difficult to see

[Screen.BackgroundPerPixel] is the property I believe I need to affect.

There is no documentation on the nature of the file I need to create.

Does it need to be something like 4000 x 4000 pixels, with a little part in the middle that's the exact shape of the non-rectangular bits, then use margins to specify which part should be positioned under the graphic?

I feel like I'm having to reverse engineer this. StarDock are there specs somewhere I can read about the datatypes required for all the possible settings?

...and to my fellow posters, PLEASE use decent subject lines... "having a problem" is NOT acceptable.
Thanks in advance.