At designtime rightmouse click on a SimpleComboBox and select "wizard ...".

This shows the following window:
(where you can easily set the necessary properties)

 
('Edit selected item' allows the user to directly edit the lookup data itself)
 
It's only necessary to set the first 2 properties in this window.

An auto analysing algorithm simply sets the other properties.
Of course you can override these other properties when they are different.


Even easier
And we make it even more easier for you!
The DataEntryForm wizard can automatically detect which data needs to be set in a SimpleComboBox. This way you do not have to do anything extra at all!
 

Null support
This SimpleComboBox can also manage null values automatically for you. A "(none)" entry is added to the list. Of course this text can be changed by your own custom text. This is a handy feature, because by default a normal ComboBox does not handle this for you.

ComboBox null related properties: