Mouse.Hit nil on toolchange (Reported by LAUProgrammer/Looah on IRC)

Not a really good description, but he explained a bit more in IRC:
Apparently mouse.Hit is nil whenever he switches tools or sometimes when going to chat.
I asked him if he actually was looking at a part, and he said yes.
I couldn’t find this bug in this forum or on github, thuss to be sure I post it here.