How do I get MB1/MB2 = MB3 operation to work?

[rnturner]

@robin_listas

I’m testing 12.3 with XFCE, and traditional X copy paste works. I use
third mouse button emulation via clicking both buttons simultaneously
(it is a laptop touchpad).

I have no problem with chording the mouse buttons on my Dell Inspiron. It’s my primary desktop that is misbehaving.