I have tried lots of stuff, too much to list at this time, but the following test program has a transparent background in XFCE and KDE. (On Slackware 14.2 64-Bit, NVidia Video Card and Driver).
https://stackoverflow.com/questions/39906128/how-to-create-semi-transparent-white-window-in-xlib It does not work in FVWM, TWM, FluxBox, BlackBox nor WindowMaker. In FVWM, transset does not work. (Works in KDE and XFCE). The XComposite extension is in place. The Visual (as far as I can tell) is 32-Bit True Color. I cannot seem to get a transparent window, no matter what. I also tried it on an Ubuntu system as well. Same problem. Basically I just need a transparent terminal for text overlay. I am sending this to the Workers mailing list as if there is something I can contribute to fix this, I would like to try. I am running: fvwm 2.6.8-4-g4e759d6 compiled on Oct 31 2018 at 08:54:15 I tried adding this to fvwm/fvwm.c: 2281 XMatchVisualInfo(dpy, DefaultScreen(dpy), 32, TrueColor, &template); 2291 XMatchVisualInfo(dpy, DefaultScreen(dpy), 32, TrueColor, &template); No luck. If a window shows up as transparent in XFCE, why would that same application not be that way in FVWM?