@Lenni
You can, and also @flameshot provides more tools and colors, but it is a "still frame" because Flameshot captures the screenshot first, and then let the user to annotate it. Therefore it is not useful if a video is playing in the background or slides are changing or moving through the code.
Side note:: I'm one of the maintainers of Flameshot ;) and I'm glad you have found it handy :ablobcatattention: