How to change the level editor controls?

[The chaser]

hey guys,

i just want to switch the 3rd mouse button with the 2nd mouse button. i dont know why, but the 3rd mouse button does not work for the level editor (on this computer) that means i can not change the center of my view/go to "track"-mode. how can i fix this?

If it is what I think, at the bottom of the level editor there is a "LT". Click it.