When editing a page, edit-able area only a small portion of the page

When I go to edit an existing page, I've noticed that the editing pane is only a small portion of the screen. The edit-able area is only like 8 lines high instead of being the entire screen. It didn't used to be like this, and since it makes it really difficult to edit a page, I'm guessing it's a bug. This is a bug I'm only seeing in Chrome. I'm not seeing this issue for new pages that I create, only when you have an existing page and hit edit. See the attached screenshots.