Have a workspace with many projects.
Open Project Dependencies (I used Settings for All Configurations), scroll through the tree with the arrows and toggle the dependencies with space, then select OK.
Open the Project Dependencies again and see that the check-boxes are not modified.
Repeat the same with the mouse and the result is that the check-boxes gets changed.
Beta5, XP32.
For large workspace, would be nice to have a built-in option (right-click or buttons) to select all and deselect all at once.
Thanks,
Daniel