(I apologize for not responding in French, but I really don't know it well enough to write in)
The CVI user interface library doesn't support ,<tab> characters. Yes, you can type <Ctrl-Tab> and what looks like a tab break is created. But if you look carefully, you'll notice that the only thing that happened is that a few spaces were inserted in the string, enough spaces to advance to the next tab stop. And you might also notice that if, after you enter <Ctrl-Tab> you start typing before the tab break, the spaces behave like spaces, and not like a real tab break.
There is no equivalent programmatic action to typing <Ctrl-Tab>.
Luis
NI