listen button BUG?

Problem: when using the keycomand for: mixer/channels: listen on/off it only works when one of the mixers is visable.
Example: select the “keycomand for: mixer/channels: listen on/off” in keycomands
Type “L” in “type in key” and push “assign”
Result: on your keyboard the letter “l” is now connected to this keycomand
Now go back to cubase, open a mixer and the “channel editor” and select a channel, type “l”
This works , the selected cannel goes into listen mode both in the mixer and in the “channel editor”
Now close all mixers, be shure the selected cannnel is still the same, type “l”.
Now the selected channel does NOT go in to “listen” mode.
Conclusion: this only works when a mixer is visable.
Should it not work ALWAYS when you have a channel (or multiple channels) selected??

pc Q6600/xp-sp3/cubase 6.05/RME hammerfall