I have a textbox on a form, and MaxLength is set to default (0 = no limit), and all of the other properties like InputMask, Format, and such are default too (empty)

However, when a user begins typing in that field, after about 20 characters or so, the textbox stop accepting characters.

The textbox is bound to a string property on an object like this ControlSource = Thisfrorm.Object.cProperty

What would make it become limited like this?