How to disallow func_button to be movable by the physgun?

I have a few func_buttons and func_movelinears on my map (for example, a garage door is opened by a button). This garage door and button can be moved around the map with the physgun. How do I prevent this? Google was not my friend today.

EDIT: Sorry, I just saw the mapping question megathread. Mods, if you want you can move this thread/post to the megathread. :facepalm:

Turn smart edit off for the entity properties.

add this:

This worked perfectly, thank you!