Controlling the alpha value of windows via some hotkey can be very useful: Read the lines of a window at the bottom through the window at the top or simply dimm the terminal currently compiling the kernel to make it look nicer and see the background image shining through.
As I have been told on #xfce/freenode this option has been removed from xfwm4-tweak-settings recently. Something that would not mind if I could still regulate translucency of windows via the respective X-properties:
xdotool windowmove 0x00d9f4ae 0 0 .... moves the window to the top left
xprop -id 0x00d9f4ae -f _NET_WM_WINDOW_OPACITY 32i -set _NET_WM_WINDOW_OPACITY 0x33 ... unfortunately that does nothing
The compositor for xfwm4 is running and it correcty dimms windows on move or resize.
Last time I checked _NET_WM_WINDOW_OPACITY was working fine, xfwm4 has been supporting this property for years...
_NET_WM_WINDOW_OPACITY is a cardinal, not an integer, so the following works:
xprop -f _NET_WM_WINDOW_OPACITY 32c -set _NET_WM_WINDOW_OPACITY 0x7FFFFFFF
ok; thx; that works fine.