It's like this :
I'm using FCK editor 1.0.0.4 (just released) under DNN 3.3.1
When I use the text box, the js file which I add to the skin doesn't have any effect in the editing area. But in other text boxes, like in the search panel or in the basic text box, that js file works well.
I think the code must be put in some place that will load the js file inside the editing area. But I just don't know where to put it. I'm definitely not a programmer.
Anyway, thanks so much for helping me!