Tags on a demo page: no more removing them by accident

On the phone, a demo page's tags sit right above the video, and a tap meant for the video could take a tag off. Now a finger's first tap on a tag's × only turns it into "Remove", and only a second tap takes the tag off. A tag taken off stays in place for a few seconds, struck through, with "Undo" to put it back. With a mouse, a click still removes it at once, with the same Undo.