This doesn't work vertically, so once bug 1893655 lands drag n' drop to rearrange tabs should be fixed.
Bug 1893656 Comment 0 Edit History
Note: The actual edited comment in the bug view page will always show the original commenter’s name and original timestamp.
This doesn't work vertically, so once bug 1893655 lands drag n' drop to rearrange tabs and to pull a tab to a new window should be fixed.