I would like to add a dropdown calender to be able to choose the shown date in a letter manually.
I found the option Format → More Controls → Date Field with assigned Dropdown property ( More Controls - LibreOffice Help ). But i am not able to click the dropdown symbol, clicking on it highlights the whole Date Field. Also the dropdown symbols is visible when printing.
What can i do?
The drop-down calendar object is meant for use in Base Forms.
When you placed it in the Writer document you would have been in design mode so when you click the object you are selecting the object in design mode. You need to come out of design mode to use the calendar. You will then be able to click to display the calendar.
When you print the document it will print the object including the drop-down symbol.
When used in a Base Form you would not be printing the Form.