When you press F1 to open the menu, it opens the Spawn/Q menu as well. Can get past this by clicking one of the tabs at at the top, but might confuse new players to Gmod/other people.
It still shouldn't spawn both though, that's the issue. Like Kaiden said, it might confuse others who might be new to the game or mode.
it will do that cus on garry's mod if u press f1 even on ur own little game in single it will show the spawnlist and shit, but the only awy ur gonna change the issue is changing the button for bb menu to a different one unless u go into options and take out F1 in the options but idk if u will be able to hit the menu on F1 after you do that problems come with simple answers and solutions just no one listens to little ol me at any point cus i dont know what im talking about
Or yknow I can just disable the event that Sandbox has by default with F1, it's not exactly a difficult thing to do.