I installed vcxsrv-18.104.22.168.1.installer.exe in Win7 64 Bit.
Dialog noframe topmost
Tk noframe topmost
Window noframe topmost
xeyes noframe topmost
noframe topmost has partially effect, but any application has still somewhat frame around and this frame can be resized. Xming-7-5-0-20-setup.exe works without that frame, see screenrecording! And notab has no effect with both. Tested with python + Tkinter and python + qt and xeyes . See video/ screenrecording http://youtu.be/Fxh5ERHTv1c (not listet)
and BTW: vcxsrv-22.214.171.124.1 does not show a symbol in system tray. I can stop it only with task manager. vcxsrv-64.1.14 shows a icon where I cat stop, etc. Is that your intention or a bug?