The Calendar is not correctly displayed in Xray's gadget definitions

Description
The Calendar is not correctly displayed in Xray's gadget definitions.

How to reproduce

1. Open a gadget definition (this particular case was seen in Test Runs List Gadget);
2. Set Range type to Custom;
3. Click in the Start/End date field, and the calendar is shown.

Actual result/Attachments
The calendar is shown to the right of the relevant gadget section:

Expected result
The calendar is always centered to adapt to the user's view/resolution.

Version

• v4.2.13;
• v5.0.2.

Environment

• Chrome
• Edge
  (Not visible in Firefox)