Hello, I was trying to run RQT bag on windows with Connext DDS and had an issue.
Although the module worked fine, it complained about not finding cairo. It was discovered when working on this issue ros2/kilted_tutorial_party#436. I had a similar issue with RQT not finding matplotlib due to which it wouldn't start. It worked fine after installing matplotlib via pip.
I am not sure if the issue is specifically with RQT bag. Please let me know if I need to open it on another repository.