THE PROBLEM
The problem is the
div with class
Settings-settings-1316548938 which looks like this:
.Settings-settings-1316548938 {
position: fixed;
}
position: fixed; creates a stacking context which wraps the new stacking context that .month-picker is trying to create (using position: relative and z-index: 99999999).
Since there are not more stacking context than:
.MuiAppBar-positionFixed-2227438490
.Settings-settings-1316548938
.month-picker
and .month-picker is an inner stacking context from .Settings-settings-1316548938 this is causing the problem.
THE SOLUTION
Easy:
.Settings-settings-1316548938 {
position: fixed;
z-index: 99; // or any other positive number
}
Why?
Because position: fixed; creates a new stacking context but without the z-index property, elements are stacked in order of occurrence.So the svg elements come after than the date picker element and that's why you need to specify the z-index on your Settings-settings-1316548938 class.
Also you must understand what I mean when I talk about stacking context. So follow the link and read the article.
Hope this helps!