Thank you for fast response.
The strange thing is that your demo works great on both iOS and Android, but mine doesn’t. This is also true for Chrome, your demo works, mine doesn’t. Would you care to take a look at: https://goo.gl/0uz2Jj ?
Unfortunately I cannot test with WP default theme as I’m targeting featured images of a CP created by the premium theme I’m using. But having it work in Firefox and Internet Explorer makes the whole situation pretty odd.
Please forget about the misalignment I reported earlier as it only occurs in Firefox 22 on an older machine, I guess it’s a hardware problem there.
Cheers!