Docked blocks are moved to the last part of the tab order

Issue
Keyboard trap - Once elements have been docked, they are moved to the side and put at the very end of the tabbing order. While tabbing through the interface with all panels docked, part of the interface is moved to the left and we lose part of the content.

Standard Level
WCAG 2 A 2.1.2 http://www.w3.org/WAI/WCAG20/quickref/#qr-keyboard-operation-trapping

Impact
Serivous

Example Link
http://demo.moodle.net/ Dock a block and try tabbing to it