I've attached a small application that demostrates an issue. The UltraCombo on the form does not have a datasource assigned but does have the Limit to List checkbox checked. When you click on the UltraCombo to display it's contents, the dropdown appears and then scrolls up after you leave the control. From that point on, all controls (including the forms min, max and close buttons do not recognized any click events.
Thank you
Clay Seifert
The reason for this issue is the UltraCombo has been limited to the list. When you drop down the list that contains nothing and the default text value you still have in the combo is attempting to validate after the control loses focus it will cause the combo to retain focus preventing the leaving of the control.
Since you created this in a test project try changing the CausesValidation property to False on the UltraCombo1, and you'll notice the validation is skipped when you leave the control.
If you have set the LimitToList property to true and you want leave the control when the text is null or empty string... setting the CausesValidation property to False is not the best solution.
Instead, why dont use the event ItemNotInList ?
c#
private void ultraCombo3_ItemNotInList(object sender, Infragistics.Win.UltraWinEditors.ValidationErrorEventArgs e) { if (string.IsNullOrEmpty(e.InvalidText)) e.RetainFocus = false; }
Actually, I think the easiest thing to do is to simply set ultraCombo.AllowNull to True.