Sessions calendar "+N more" popup not properly visible on Monday and Tuesday blocks

[OeschMe]

Describe the issue

When clicking the "+N more" link in the sessions calendar at Monday and Tuesday columns the popup is showed under the side menu.

Plugin versions

5.6 b 2883

Additional information

This could be fixed by either forcing Mon and Tue popups to show on the right of the date block or by setting the Z-index higher than the menu.

[AuroraLS3]

This is a duplicate of #3668

Unfortunately changing z-index does nothing since sidebar is rendered as static so it is in different render context from the popover (Tried it)

[OeschMe]

I dis some testing my self, changing fc-popover fc-more-popover fc-day fc-day-mon fc-day-past fc-day-other classed box's (Monday popup) style data from left: 10px; to left: 14em; seems to work.
Seems to work for Tuesday too. This shifts the left side of the box aligned with the calendar views left side.
For small screens Wednesday could also use that shift.

This isn't a huge issue, but if you have the time and crayons to fix it it would be nice. It's probably rarely used feature anyways, so not a biggie.