Please make it automatically show the dictionary again it saves a lot of time
I've just made a followup change which changes the button into a toggle between "Show Dictionary" and "Hide Dictionary" and the setting persists within the same browser session, so that once you've clicked "Show Dictionary" once you won't need to keep clicking it for each new card you open. This isn't exactly what you asked for but I hope you'll find it a reasonable compromise.
(I added this feature because the external dictionaries add a lot of clutter and can feel like they are getting in the way, particularly when you want to scroll the main page but end up scrolling within the external dictionary instead. Also, they sometimes hijack the keyboard input focus which is annoying when you are trying to edit the translation for example)