Hello fweeee,

You are right - you could use the 'AfterCloseUp' event. You could check in it if the left mouse button is clicked and if this was done on a cell in the WinCombo control.

Below is a my code sample:

private void ultraCombo1_AfterCloseUp(object sender, EventArgs e)
        {
            if (mouseCaptured .Button == MouseButtons.Left &&
                ((Infragistics.Win.ControlUIElementBase)(ultraCombo1.DisplayLayout.UIElement)).LastElementEntered != null &&
                ((Infragistics.Win.ControlUIElementBase)(ultraCombo1.DisplayLayout.UIElement)).LastElementEntered.GetType() == typeof(EditorWithTextDisplayTextUIElement))
            {
                //Your code here...
            }
            
        }

        MouseEventArgs mouseCaptured;
        private void ultraCombo1_MouseClick(object sender, MouseEventArgs e)
        {
            mouseCaptured = e;
        }

 Please review the above code and feel free to let me know if I misunderstood you or if you have any other questions.