Shared Screen and DVD movies
This is a silly copy protection measure. If you use VLC rather than Apple's DVD Player you get no problem at all.

First, go to System Preferences > CDs &amp; DVDs and change the setting for When You Insert a Video DVD from DVD Player to Ignore or choose other and select VLC 2 in your Applications folder.

Now when you insert a DVD VLC 2 will run and should autostart. No grey boxes.