you need to presss numlock (it either needs to be on for the texture commands)
also another hotkey I forgot about: + - to scale the texture (hold shift or ctrl to only do it on one side)
turn off bsp:
select all meshes you accidently bsp-ed
then open the console and enter the command: UNBSP
then enter the command: BSP
(or hotkey: 0)
to rebuild the bsp mesh (in this case to get rid of the preview geometry for it)
you can also select them one by one in properties mode (6) hold Q or E and select BSP OFF