Before I updated to Lion, whenever I would mount a disk image (.dmg) the Finder window that would pop-up would always have a little 'jellybean' in the top right corner that would expand this window into a 'full' Finder window with the left-side panel, thus allowing quick and easy access to be able to eject the disk image.
I do not know if this feature has been completely removed from the OS or if its just disabled. Is there a way to get this back? I miss the jellybean!