In the administrative area, under "Security", if I click on a member, a box pops up. That box is about 560 pixels wide. How can I make that box 750 pixels wide?
...but with a specific size.
The MemberTableField actually has a method called setPopupSize() which you can use to set the width and the height. You'll probably hvae to fetch the table field via a decorator which can be rather tricky.