IE11: calendar date range shows days in white on white

[mattab]

on ie11 there is an issue with selected date on calendar.

The date appears in white color fonts.

This appears only in this browser and just after inspecting element with the debug tool, problem disappears.

[mattab]

Attachment: ie11 screenshot
Individueller Zeitraum.png

[tsteur]

In e817ea9: fixes #4972 IE10/11: calendar date range shows days in white on white