datepicker on input with even vertical padding inside a position:fixed div appears far from the input

[Valentin Plamadeala]

here's the jsbin for this: ​http://jsbin.com/wapupa/edit?html,css,output

happens only on the latest version (using jquery 3), previous version using jquery 1 works ok

the datepicker input has to be inside a position:fixed div and the document scrolled down, if the input vertical padding is an even number, the datepicker popup will appear off depending on how much the document is scrolled