I don't know if you caught this, but like the spinner where things don't fit, the same happens with the edit fields. Even when I have an existing string of say 20 chars, and edit, it is a wider field but the text on the left is not the beginning of the text. I say make the text field as wide as the largest string length (average character width ABCXYZ123) or to end of the listbox (right), whatever is smaller.
For example it may start with a blank string and you have to type 20 chars, you only see 3 at a time.
UPDATE: Enabling "autosize" property fixed that issue
It doesn't fix it for spin controls however, even tried setting it specifically on it.