Presumably this would just always happen automatically as in our Kirigami apps, as adding an option to do something automatically would be extreme over-configurability. :) However I'm not sure how well this would work with existing configurability. If I've manually opened my Information Panel, would it close without my permission when the window becomes small? And we would also have to handle/avoid the case where you've moved the information panel to be in a location where it's not taking up any additional space--for example, below the Places panel. This is where I have mine. In this configuration, its being open or closed does not need to bear any relation to the window size.