extract teams chat from teams groups list

[Jerkieken]

Is there a way to divide the complete teams chat window from the teams group one in the application?

Today, If I'm working on documents in the teams channels (having f.ex. an excel worksheet open) and someone starts a chat conversation with me, the open excel document is always automatically closed and I have to reopen all documents again from the channel. 

[#2]

I'm not sure I understand you correctly, but it looks like you're asking to open chats in their own windows. Have you tried toggling the "Open new chat in" setting value to "New window"? You will find it under the main Settings window.