Fields dialog box stays open

Question re Writer 4.2.4.2:

After editing the footer line in a document to include the chapter number in front of the page number (to show something like 4-11 for page 11 in chap. 4), the Fields dialog box stays open. I can’t close it, neither by clicking the Close button in the dialog box, nor by clicking the Close button of the window.

Interestingly, when closing and reopening this document, the Fields dialog reopens as well (just as the Navigator window).

Does anyone have an explanation for this?

TIA,
Hans