Position of calendar is in the wrong position with Typescripts

[TBatist]

I have created a custom HTML-element using Lit-element. It contains an input element that will trigger the datetime-picker. The code is shown below.

When I click on the input, the calendar opens. However, the calender normally opens somewhere in the top-left of the screen, instead of under the input field. When I set the parentEl to the input, the custom element in the HTML, or the parent container, the calendar is rendered somewhere above the screen (for example, the style of the rendered container is top: -700px ). I tried to manually set the position in Javascript/Typescript, but this doesn't work.