How to Stop mouse Copy/Paste

I was wondering how to make the mouse under dosemu work like a DOS mouse. In other words
stopping the keyboard input buffer from filling with whatever is in the clipboard when the middle
mouse button is pushed. I have applications that use all three mouse buttons but when I hit
the middle button it total wipes them out by filling the keyboard with unwanted characters. I have
looked through the documentation and Googled but so for haven't discovered a way to disable copy/paste in dosemu. I tried capturing the mouse in a the X window but still no luck. The version of dosemu is 1.4 under Ubuntu 7.10. Also running under X in dos box.

Thanks in advance,
Mike