I used to be able to click on the middle button (not scroll) and it will pull up the OS menu. For some reason this feature is no longer availible. I have mbuttonpan set to 0, but did try changing it to 1 and it did not help. Thank you.
Probably to fix this you need to take a look at your acad.mns file and refer to the acad help topic "Assigning commands and functions to mouse and digitizer buttons"
But instead of using the last line of the example "'Zoom;Window" you would want it to look something like $P0=SNAP $p0=* that is if your pop0 is used for the os menu (which should be located below the last aux string). Your aux1 and buttons1 strings should be the same. If you have never messed with the mns file you must be carefull & make sure you back it up before making any changes.