Just tested with 3 listers opened, all in commander mode, to different directories. No errors at all in the right click menu on the taskbar buttons. Tried it with a top oriented bar, and a bottom one (which is when I used to have problems with taskbar3).

Had the same results with 1.37 and 1.38 (which I am currently using) - no errors. I'm using Dopus 8.1.0.8 Unicode version. (btw, just noticed there's an 8.2 out.)

Also, there is an option to reassign the clicks on the buttons. It's under "Taskbar Button Events."