I find that 90% of the time that I go to the deck editor, the first thing I do is click "hide card pool". Either I'm there to check the contents of the deck, or I want to make some changes (but usually I first have to choose the cards I want to remove, so I hide the pool anyways).
I can see how this could be confusing for a new user, but it would be nice to have as an optional tickbox in settings. It would literally save me seconds every day!