Includes all the new user-requested changes of ver 0.4.1 plus incorporates ‘XPC Native Wrappers’ for additional security.

1. Smart-Delete now traps for ‘Alt’ and ‘Ctrl’ keypresses. These combination keypresses will no longer erroneously trigger mail deletion.

2. User defined keyboard shortcut – User can now set which key they would like to use to trigger mail deletion.
   (The default letter is ‘d’, but by editing the script file any letter can be used. Just find the following line of code near the beginning of the script: var TheDeleteKey=’d’; And change the key letter to whichever one you like. Be careful, though, not to select a shortcut already being used by Gmail!)

http://smart-delete-button.blogspot.com/