### **Environment**:

Your OpenProject Version: **10.2.1**

### **Steps to reproduce:**

1. Begin of the insertionCreateEnd of the insertion Begin of the deletion Either configure OpenProject to auto set todays date as start date on new work packages and createEnd of the deletion a milestone in a Begin of the deletion project, or create a milestone in aEnd of the deletion project and set a date on it.
2. Edit the milestone and try to delete the date.
3. There is no error but no way to save it Begin of the insertion
1. EvenEnd of the insertion Begin of the deletion evenEnd of the deletion after you click done in the calendar Begin of the insertionselector,End of the insertion Begin of the deletion selector.
4. Try to leaveEnd of the deletion the date Begin of the insertionpicker simply closes. However theEnd of the insertion field Begin of the insertionremains open.End of the insertion Begin of the deletion and it stays bordered in purple (editing).End of the deletion
Begin of the insertion4.End of the insertion Begin of the deletion 5.End of the deletion Try to leave the screen and you get a message telling you you are about to leave without saving changes. Begin of the insertion
5. Like in other fields an Enter saves the empty field, but a focus loss does not.End of the insertion

### **Expected Behavior**

Begin of the insertion* Clicking somewhere elseEnd of the insertion Begin of the deletion IEnd of the deletion should Begin of the insertionsubmit the date field, like it does for all other fields.
* We could think about submitting when clicking on "Done" in the date picker. However, we shouldEnd of the insertion be Begin of the insertioncarefulEnd of the insertion Begin of the deletion able to delete a set date, especiallyEnd of the deletion as Begin of the insertionthe wording in German is "Schließen". So it makes only sense, if that can be changed.End of the insertion Begin of the deletion Milestones cannot have child work packages.End of the deletion