Unfortunatly, I was using non default containers. Nevertheless, I set the value you advise me to 100 (after having closed all chat windows), but with no effect on the separator which is still inaccessible.
Now, I am trying to setup the container when opening a chat room, but without success : if I change the room to the "Default container", the next time I open it, it is again not in the "Default container".
And even just after moving it to the default container, I still doesn't have the separator to increase the input field. However, the value in "CNTW_Def_SplitterY" is still set to 100.
And, by the way, for what function the property "CNTW_Blob_SplitterY" is used ? (I accidently modified its value when trying to modify "CNTW_Def_SplitterY").