error 13811 : The specified indexer type does not match any

I am having problems with this code compiling :

define private variable tileGroup3 as DevExpress.XtraEditors.TileGroup no-undo.
method public DevExpress.XtraEditors.TileItem getTile(p_name as char):
    return this-object:tileGroup3:Items[p_name].
end method.

the error is

The specified indexer type does not match any type required by this object. (13811)
A class can support one or more indexers.  The index value is essentially a key that identifies a unique member of the class.  
The class implementation determines what the data type of each indexer is.  However, in this case you have specified a type 
that does not match any of the indexers implemented by this class.

but given this documentation, I can't see why [I don't want to say , but have to, that yesterday this compiled. I've restarted OEA since .. and now it won't compile]

TileGroup.Items Property

Provides access to a collection of TileItems used by the current TileGroup.
Namespace:DevExpress.XtraEditors     
Assembly:DevExpress.XtraBars.v12.2.dll
Syntax
 
 

public TileItemCollection Items {get; };







Type: TileItemCollection 
A TileItemCollection object that stores TileItems used by the current TileGroup. 
 







TileItemCollection.Item Property








Provides access to the TileItems in the current collection by their names.

Overload list
 
 



 
Name
Description



TileItem this[string index] {get; set; };
Provides access to the TileItems in the current collection by their names.



TileItem this[int index] {get; set; };
Provides indexed access to individual items in the TileItemCollection.



See Also
 
 
TileItemCollection Members
DevExpress.XtraEditors Namespace