Document Properties window reopens too small

Summary:

When the Document Properties window is opened from the File Menu for a second time, it is too small and cannot be used.

Steps to reproduce:

This occurs on Ubuntu 20.04 with Inkscape 1.0 (6e3e5246a0, 2020-05-07) as installed from the Ubuntu Software Centre. It does not seem to occur on Ubuntu 18.04 with Inkscape 0.92.

Start Inkscape with a new blank document. Click Document Properties in the File menu. The Document Properties window opens normally. Click the X button to close it. Click Document Properties in the File menu again. The Document Properties window opens but it is small. It cannot be resized and most options are inaccessible.

The exact same problem occurs when working with a document. It must be saved and reopened before the Document Properties can be reviewed or changed.

Version Info:

- Inkscape Version: ... <!-- (run inkscape -V or copy from Help → About Inkscape, top right) -->
Inkscape 1.0 (6e3e5246a0, 2020-05-07)
- Operating System: ...
Ubuntu 20.04
- Operating System version: ...