For the moment I can only launch the X11 full screen session, but I don't understand how to run X11 apps on windowed mode, like Doug and Sean are showing on their screenshots.
Unlike the commercial X desktops like Exceed and PMX, XFree was designed to run full screen and not operate in a seamless windowed mode, nor does it share the Clipboard w. OS/2. However, you should be able to switch between XFree and PM using Alt-Escape.
Unfortunately for my use, PMX is too sluggish. Since my OS/2 desktop is run within a Linux VM, I'll just have to minimize OS/2 to access the few Linux applications I have been unable to replace with native PM alternatives. I have an Exceed license I formerly used w. Windblows and the performance was fine, so I'll need to revisit why PMX is so sluggish with OS/2.