Position relative to parentEl

[bjornandrip]

Describe the bug
I have a div positioned far down on a page that has a datepicker. This datepicker shows a litepicker instance when pressed which positions itself relative to the parentEl but calculates it top attribute relative to the body.

To Reproduce
Steps to reproduce the behavior:

1. Create a div which has margin-top: 500px for example and position: relative
2. Initialise a Litepicker inside the child div with it set as its parentEl.

Expected behavior
The litepicker is positioned relative to the parentEl in step 1 and gets the correct top positioning relative to its parent.

jsfiddle.net / codepen.io / etc
Please provide a link with bug.

Additional context