Language list is displayed with empty space and looped

[Korb]

Describe the bug
When I open the drop-down list of languages ​​supported by the application, I see a large empty space after the last item in the list. This space disappears if I use the up arrow key or the mouse wheel to go to the beginning of the list and then return to the end of the list.

To Reproduce
Steps to reproduce the behavior:

1. Set the application interface language to a language from the end of the language list.
2. Open the drop-down list with the language list again.
3. Make sure that there is an empty space after the last language in the list.

Expected behavior

1. The drop-down list contains only clickable items of languages ​​supported by the application, and nothing more.
2. If the first language is highlighted in the drop-down list, pressing the up arrow on the keyboard does nothing. If the last language is highlighted in the drop-down list, pressing the down arrow on the keyboard does nothing.

Screenshots

** Windows (please complete the following information in case you encountered the bug on Windows):

• Microsoft Windows 10.0.19045.4957
• Workrave 1.11.0-beta.14