what's the type of the controlsource of the offending grid column?

>I have a class of a combobox the use in a grid.
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>I can add the combobox to a grid manually and it works fine.
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>If I try to add it programatically I get the error message "Value : Data type mismatched".
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>As added to grid there is nothing in the combobox control, no control source, no RowSource or RowSource type. Everything including the value property is at it's default except for Style set to 2 - Dropdown List
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>All of this work of assigning RowSource,Bound etc is done in the Init method which has not fired when the error occurs.
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>I add other combobox's to the grid using the same grid populating code and they work.