Normally, click with the MMB rotates the view in the 3d window. Today, for no reason as far as I can tell, the MMB now works like the LMB, where if I click and drag it makes the little line you use to make a V to resize, or a circle to rotate, etc.
It’s really annoying. What’s worse is that when I finally confirm whatever change it wants me to do, (and I can’t abort the command with RMB) THEN it starts rotating, and on some weird access.
I don’t recall changing any settings that have anything to do with the mouse. What’s up?
I’ve futzed with a few controls up there, most notably “Emulate 3-Button Mouse”, but to no avail. I’ve found that double clicking the MMB makes it act like “normal”, but it was fine for the previous couple of weeks I’ve had Blender; I don’t know why it would change now. :-?
Make sure and check your mouse settings in windows. Some mice you can assign button lock and other functions to different buttons. It might have something to do with that.