When a page has width=device-width set, the double-tap-and-hold zoom gesture doesn't work anymore, even when the tap hit only elements that don't handle click events.
Without width=device-width set: http://output.jsbin.com/femivot/
With width=device-width set: http://output.jsbin.com/lecici/
What happens: Double-tap-and-hold zoom doesn't work on the second link (https://www.youtube.com/watch?v=ashLZBGPRhg)
I believe this might be a side-effect of the solution from https://bugs.webkit.org/show_bug.cgi?id=150604, but shouldn't the zoom functionality not only be removed from clickable elements? So if a tap hits no element that is a link, has an onclick handler bound or a focus-sensitive pseudoclass - basically if a tap has no effect - the zoom should still work after a subsequent tap-and-hold?
I just ran into this as well in the wild with Safari iOS 9.3 beta 3: https://www.austrianwings.info/2016/02/daallo-airlines-war-eigentlich-turkish-maschine-das-ziel/
Before finding this bug here, I filed rdar://24553762
With iOS 9.3 beta 5 zooming with double tap works again on the site I mentioned above. I can't tell for sure though, if this is due to the issue being fixed in WebKit or maybe the site has been changed (though the width=device-width is still set there).