SimpleType used in ListGridField results in a warning log

[daniel_h]

Hello,

using SmartClient 8.3 Pro (latest nightly).

For the purpose of currency formatting,
our system has a SimpleType MyMoney defined:

isc.SimpleType.create( {
	name :"MyMoney",
	inheritsFrom :"float",
...

This SimpleType is used in a ListGridField:

<ListGrid>
   <field name="Amount" title="Amount" type="MyMoney">
</ListGrid>

The functionality works fine, the list grid field shows the value with correct currency formatting.

However in the log file, there is a warning saying:

"/ListGrid[@ID=openInvoice_LG_FORM_SyNewDebitDocumentView_1369137364105]/fields/2/field[@name=Amount]":{
        recordPath:"/ListGrid[@ID=openInvoice_LG_FORM_SyNewDebitDocumentView_1369137364105]/fields/2/field[@name=Amount]",
        type:{
            errorMessage:"Must be one of [text, boolean, integer, float, date, time, sequence, link, image, binary, imageFile]."
        }
    },

My question is, why is this warning logged?
It is "just" a warning, but instead of simply ignoring it, I would rather like to know, is there anything wrong with the above code?

Thank you.
Best regards, Daniel