Hello, Schmetterhahn
Welcome to the Microsoft Community.
Hello, I'm sorry to hear about your problem with the menu bar malfunctioning when using Sweet Home 3D.
Firstly thank you for the video and the information, you seem to have carried out some of the steps to fix it, which is great and shows you are a learned scholar.
Your configuration is fully capable of using this software, so the hardware aspect is satisfied.
Based on your video, does this phenomenon occur with other software.
If it is only in this software alone that you are having your problem, this could also be a problem with the software itself, try uninstalling it or doing the repair steps in the control panel.
To rule out other software, you can do a clean boot and run the software alone once and see if it is normal:
How to perform a clean boot in Windows - Microsoft Support
Disclaimer: A “clean boot” starts Windows with a minimal set of drivers and startup programs. It helps to determine whether a background service is interfering with your game or program and to isolate the cause of a problem. These steps of "clean boot" might look complicated at first glance. However, to avoid any trouble for you, please follow them in order and step-by step so that it will help you get back on track.
Also I have found the official forum for the software for you and it seems that similar issues have been raised:
Sweet Home 3D Forum - List all forums
Disclaimer: Microsoft provides no assurances and/or warranties, implied or otherwise, and is not responsible for the information you receive from the third-party linked sites or any support related to technology.
Thank you for your time and effort in resolving this issue.
Best regards
Bobhe | Microsoft Community Support Specialist