>Yes...
>
>While one button has the FOCUS waiting for action, as soon as I hit a letter, the control goes to a second button with a hot key being the same letter.
>
>This is causing that the system activates the second button; consequently, triggering an unwanted action.
>
>Is there any way to avoid this ?

Generally, this is standard behaviour. But, you can put code in the keypress of the Buttons so that only alt key combinations work. One of the parameters passed to the method by VFP is nShiftAltCtrl. If the Alt key is used, this number will be 4. So if this number is not 4, you could have:
if nShiftAltCtrl <> 4
nodefault
return 0
endif
DoDefault()