[Inkscape-user] Windows 10: Menu commands of Inkscape do not appear

Hello.

I installed the latest version of Inkscape on Windows 10.

Three effects I recognize:

1 Inkscape needs extremly long to start (about 15 seconds), much longer than every other application (about 1-2 seconds) on my PC with an SSD.

2 When I click any entry in the menu toolbar, an empty rectangle appears. Not any command is visible.

3 When I hover over any symbol in the vertical toolbar as well an empty rectangle appears.

How can I solve the problem please?

Thanks.

Andreas