WindowMaker DockApp does not show, or show in regular window
Normally DockApps should be displayed in special mode, so they can be docked in one of the screen corners. They also does not have titlebar, and does not require to be placed manually (if this is set up in Window Maker).
Some old DockApp applications are somehow incompatible with recent WindowMaker (tested on 0.91+), and either does not display at all, or display in regular “window”.
I didn’t see confirmation of that behavior, so maybe this is only my issue (but on a few machines) but solution I found is to fix the source code bye changing one line of it. Search for res_class string in the source and change right side of the expression to the "DockApp". Recompile.
something.res_class = "anything";
something.res_class = "DockApp";