Use Provider property to select the GUIx component implementation:

After setting the Provider property at design-time, save the form and corresponding implementation unit will be automatically added to the form "uses" clause. At run-time you will need to add the corresponding implementation unit by hands to the "uses" clause. When corresponding implementation is not linked into application, then an exception may be raised. See the corresponding component description for supported implementations. 

Note, when Provider property value was switched from one to another value, then developer may need to delete implementation units for old Provider value from the uses clauses. Eg, switching from 'Forms' to 'FMX' requires to delete uADGUIxFormsXxx units. 

If Provider property value is not explicitly assigned, then default value will be used. By default it is 'FMX' for FireMonkey based applications, 'Console' for Windows console applications, 'Forms' - otherwise. The TADGUIxWaitCursor.Provider or uADGUIxIntf.FADGUIxProvider global variable allow to specify the default GUIx provider. 

Provider property value must be assigned before first component usage.

property Provider: String;