With Teiid Designer, user can't set "System Table Access" for "VDB Data Role" with a small display

Description of problem:
With Teiid Desitner, user can't set "System Table Access" for "VDB Data Role" with a small display

Version-Release number of selected component (if applicable):
Teiid Designer：7.7.5.v20140302-1621-H4-Final

Steps to Reproduce:
1. Set display resolution as "1024×768"
2. Open VDB file
3. Click "add data role" button

Actual results:
User can't set a check box for "System Tables Access"

Expected results:
ModalPanel has a scroll window, so user can set it