i do not got the solution horizontal scrollbar should allow to show the trailing "aaaaa" for "fils"and it does not

I understand your question, and thats a bug in whatever Tcl/Tk code is responsible for that

Sure you might be able to workaround or fix it yourself .... like I said, good luck with that :D

is it possible to clic on "+" so that node open but procedure clic is not called ?

Sure, why not, but you will have to play with the options, the bindings, and figure stuff out :)

It this were Tk.pm, you could just use Tk::WidgetDump to view bindings and figure stuff out

or view the sources to figure that stuff out,

but since this is Tkx, you would have to hunt down the Tcl sources to figure it out

The docs mention selectMode ... like I said, good luck :D