Click the Blank! button turn the projection display black. In the Projection preferences, you can choose between instant black and a fade-out function.
Click the Freeze button to freeze the current display on-screen. Even if you select a new playlist item to display, or change the formatting and redisplay the item, the projected image will not change.
If you switch programs, Worship LIVE! may not be able to maintain the frozen or blanked screen. But as long as you stay in Worship LIVE, the display should remain fixed.
Once you're ready to resume "live" display, deselect the Blank! or Freeze buttons.
From almost any place in the program, you can hit the F11 key to blank or unblank the Projection display. You can also hit Ctrl-F11 to close the projection display.