Please note that this is the US Q&A Forum, any content should be posted in German. However, I will still provide an answer in English based on your initial response.
Hello Alfred Herler,
This appears to concern Affinity’s Object Selection feature rather than Windows itself. Microsoft Q&A isn't the right place to troubleshoot Affinity-specific functionality.
Please contact Affinity Support or post in the Affinity forum, including your exact Affinity version and a description of what happens when you use Object Selection.