there is a small bug with urgency hint in rxvt-unicode: it sets it even when the window is focused, which is inconsistant, and cause an unneeded notification by the WM.
It can be tested by enabling this in .Xdefaults:
and make a beep :)
The following (trivial) patch correct this.
Created attachment 167395 [details, diff]
Forgot to say that the very bad side of this bug is that you need to unfocus and focus again the window to make the urgency hint disappear, which is very boring.
Thanks for the patch! Which version of x11-terms/rxvt-unicode are you using (or have you tested with both)?
I tested it only with rxvt-unicode-9.05.
So, when will it be in portage ? Debian already did it ! :)
This fix is included in 9.05-r3.