it still would be a good idea to try running the game with all other addons disabled and check if this happens. you also can disable addons through gmod's in-gamr addons menu on the main menu, which has "disable all" option, and a possibility to search for specific addons to enable/disable

It fixed itself for some reason?

I got the same bug. and fixed it myself. Apparently either the addon "Combine Props Reskin" by MatVeicher or the "Gestures Menu and Commands" by Bell might be causing the issue.

No picture too, but to describe it; the gizmo only renders in a small around 218p-sized box on the top left corner of the screen, it can still be interacted on the ragdoll, and you can still select bones normally but there's just no visual indication since the visual gizmo only renders on that corner.

i recall that this issue was generally caused by some no more room in hell sweps as well, maybe due to them taking over some rendering hooks as i also recall some people saying that these sweps were making the usual crosshairs not appear even when those weapons were not being held by the player

引用自 PenolAkushari：

i recall that this issue was generally caused by some no more room in hell sweps as well, maybe due to them taking over some rendering hooks as i also recall some people saying that these sweps were making the usual crosshairs not appear even when those weapons were not being held by the player

Yep, just tested it: The addons "No More Room in Hell PSE Deer Hunter" and "No More Room in Hell Military & Police Weapons" by Полковник is causing the problem