Category editing screen is empty

[xaver-ius]

When I click -> Settings -> Categories I get an empty screen. I can go back to the calendar view.
I'm using WebCalendar V1.9.10 on my homepage.strato.de with Firefox 120.0.1 on Windows 10, 64Bit.
I have activated the categories in the settings, upload icons activation doesn't matter.
Is there any idea what I'm doing wrong?

[xaver-ius]

I added a directory /wc-icons and now I can edit categories :-)

[craigk5n]

Note that in v1.9.12 we get rid of the wc-icons directory and move the icon images into the database. So, this should not be a problem with v1.9.12 and later (once it is released).