#Windows
Scott,
I believe the BACKDROP flag is only looked at/honored when the window is
opened. Consequently, the only way to do what you want is close the
window, and re-open it with the configuration you desire. You could always
open a second window and then close the first window if you don't want
things to disappear during the transition. (This latter approach would
tend to fragment memory a bit more, however).
Hope this helps…
…BobR