Yes, as euphraties the idea of the addon is the ability to hide it when not needed. Obviously it is better if it can be kept inside the panel but it isn't a tardis
That said, if you place the pallypower window where you want it to be when you are in raids you can then switch to your healing window or chat window etc and it will be hidden until you want to switch to it.
The reason I wanted a screenshot so that I could see how it expanded as the group/raid grew so that I could see if there was something I could programmatically do to deal with most instances.