How to catch the selection change event of CExtGridCellComboBox?
To catch the selection change event, create a CExtGridCellComboBox-derived class and override the CExtGridCell::OnPopupListBoxSelEndOK() virtual method, which should return a value from the parent method and perform your custom actions. The OnPopupListBoxSelEndOK() virtual method is called to handle the final selection change event of the list box control in the pop-up menu tracked by the built-in button.
