Yes I do it all the time for "type-ahead" searches. add a timer to your form. Set it's enabled property to false. Set the interval to 15 seconds.

Timer::Timer
this.enabled = .f.
this.reset()
thisform.getselectedentriesperthecomboboxvalue()

ComboBox::KeyPress
LPARAMETERS nKeyCode, nShiftAltCtrl

if not inlist(nkeycode,13,9,...)
    thisform.typeaheadtimer.reset()
    thisform.typeaheadtimer.enabled = .t.
else
    thisform.typeaheadtimer.enabled = .f.
    thisform.getselectedentriesperthecomboboxvalue()
endif

Try this !

Glenn