Merge remote-tracking branch 'marc1706/ticket/12542' into 3.1.x
* marc1706/ticket/12542:
[ticket/12542] Use more specific CSS for drag-n-drop
[ticket/12542] Do not use browser specific css for outline
[ticket/12542] Properly check if textarea is undefined or null
[ticket/12542] Use extended CSS for all browsers
[ticket/12542] Rename javascript method and add doc block
[ticket/12542] Add different outline colors for body & textarea
[ticket/12542] Add initial drag-n-drop animation