Data Grid Masked Edit not using padding when editing

I populated a datagrid via the datasource.I have a column that is a masked text box for a date, set to short date.  The datasource column is a date time.

When displaying – it shows the padding correctly, when editing – it removed the padding on the left and shifted the data to the left.

Also – on the mask edit screen – it gets cut off – what is the “USE……..” check box full description  (see screenshot)?