Would like to see this.

Would like to see this.

This should ideally work as it does in Chrome. Lift a tab from one window (or if it is the only tab open in its own window), and drop it onto the tab line of the target window to collate the two windows into one. I've had this happen accidentally with a third window open underneath, but am unable to replicate it with any success. This should be less clunky than whatever happens during that process anyways. Drag and drop to collate tabs/windows.