all dmx channels work well, except one [fixed]

[gilles le bec]

all my channels DMX works well, just one doesn't work, the first .
in the DMX level panel, i can see the first channel with another color than the other ones.
the channel seems to be a little more grayed, it seems to be reserved for something else.

is there anyone who can help me .
thank

[support]

Gray color means the channel is patched to a dmx input.
ControlBoard > dmx & midi patch > dmx input tab