Adjust tables to prevent double vertical scrollbars in new UI
Test the VM page (with several VMs) plus the disks and or jails page, with several disks or jails. All of these should resize gracefully without showing the 'double scroll bar' (actually, we should never see the outside scrollbar), even when you check one of the disks or jails and the header gets bigger.
The tables for Disks, Jails and installed plug-ins have a checkbox feature which, when checked, adds a large topbar to them, causing them to overflow the page and produce a second vertical scrollbar. Also, the VM table has a huge header to be taken into account.