You might put a transparent decoration on the front panel so that using the mouse is useless. The idea is to finish your VI, put a decoration (one of the squares) on the front panel and make it big. If there are any controls that you can still see, select the decoration and move it to the front (look on the menu bar of the VI on the same row as the run arrow). You should not see any controls. Now use the paint brush tool (from the tools palette) and color the square transparent. You may need to use a decoration from the classic control palette to get a completely transparent effect. Now when you run the VI, the user can click but nothing will happen. The user can still navigate with the keyboard though.