### Steps to reproduce

1. Go to a WP and open the datepicker

2. As start date enter 2025-03-19

3. As due date enter 2025-04-19


### What is the buggy behavior?

* Begin of the insertionWhen entering dates, only the first part of the full-calendar is used.

* For example, if the finish date goes from the month on the left to the one on the right, the calendar scrolls so that the finish date is in the first calendar instead of the selection going to the second calendar. (See video below)

* In this case, theEnd of the insertion Begin of the deletion TheEnd of the deletion flatpickr shows April and May Begin of the insertion(instead of MarchEnd of the insertion and Begin of the insertionApril) andEnd of the insertion thus only half of the dates


<img class="image_resized op-uc-image op-uc-image_inline" style="width:432px;" src="/api/v3/attachments/341411/content">

### What is the expected behavior?

* If both dates fit in the view, they should be shown Begin of the insertion

* In this case, it should be March and April. It should not switch to May.


### Video

<figure class="image op-uc-figure"><div class="op-uc-figure--content"><img class="op-uc-image" src="/attachments/341553/datepicker-only-uses-first-part-of-mini-calendar.gif"></div></figure>

End of the insertion Begin of the deletion


End of the deletion ### Environment information

**OpenProject version**

15.4

**Browser**

* [x] Chrome
* [ ] Firefox
* [ ] Safari
* [ ] Mobile Safari
* [ ] Other (please specify)

**Operating System**

* [ ] Windows
* [x] Mac OS X
* [ ] Mobile iOS
* [ ] Mobile Android
* [ ] Linux (please specify distro)
* [ ] Chrome OS
* [ ] Other (please specify)

**Language**

_German_