How to remove "Ctrl+Alt+#" keybind for window switching?

Is it possible to remove the default "Ctrl+Alt+#" keybind for switching windows?

I searched everywhere in the ISboxer config tree and found nothing relevant.

[bob]

Under character sets, your character set, then Slots and the Number (i.e. 1, 2, 3).

Select the number. On the lower right hand pane, at the top....

[lax]

For future reference, during the Quick Setup Wizard you can check the "I have an Alt Gr key" on the last page, and it will not set up these Hotkeys (because Alt Gr is Ctrl+Alt, and these Hotkeys would prevent typing things like @ via AltGr+2).

<sheepish> did not occur to me to click on those numbers.
and there are lots of other goodies under there.

thank you very much!