One of the things I love about FireFox is it's nice feature of 'undoing' the close tab. If you work with too many tabs you know how cool this feature is.
I was wondering how useful this feature would be in Eclipse. I usually work with tens of FileEditors which keep on growing as I work, to limit my efforts fumbling around a large pile of Editors, I always turn on a useful preference from 'Preferences->General->Editors : Close Editors Automatically'. This is not enough, I still have many editors open and unfortunately it's not too hard for me to close useful editors by mistake, Ctrl+Shift+R helps though. Not sure about you but this feature will be a nice one to have for me.