Steps to reproduce:

1. Login to backoffice.
2. Go to Admin / Roles.
3. Click on one of functional button - "Assign to Users / Groups", "Copy" or "Edit".
4. Verify right side menu appearance.

Actual result:

See attachment.

Right side menu at the bottom has too short edge.

Expected result:

Right side menu edge at the bottom (Discard changes button) should be the same like at the upper side (Save button).

Comment:

The problem exist also on each "edit" view in Admin section.