That lead me to believe that error happens because WebCombo is not initialized in some way and clicking the cell does that initialization. So I tried to simulate that behavior programmatically, by entering and immediately exiting cell edit mode:
// to prevent error - showing and hiding dropdown var oCell = igtbl_getCellById(sCellId) oCell.beginEdit(); oCell.endEdit(true);
where sCellId – is ID of any existing cell that uses dropdown as an editor. And Bingo! the error went away. Also beginEdit/endEdit happen so fast, so even though technically they show and hide the dropdown – in reality nothing appears on the screen.