Fix display of recurring multiday events

If an event did not recurrOn a day in the currently selected
date range but recurred before that and was "still happening"
it was not painted.
Now we check for all recurrences that "still happen" on the
first day of the selected monthview.


(cherry picked from commit 99f24760b2d30a8abbf63f0a7247415578f32deb)