Expandable Headers

I remember seeing too many requests to make the headers collapsible, if the to/cc/bcc are too many. It really takes up a lot of space in the preview pane and makes the mail invisible in the pane. I have added a ‘+’ ‘-‘ button before the header to Expand/Collapse. Also a link ‘…’ at the end of the headers. Currently my patch picks up a fixed count from gconf to show. In long term, I would prefer to decide based on the font size/screen width. I have put a screenshot for the same. Also it uses a hard coded icon for the header. Im not able to use any from the them, since nothing really matched, and Im not able to find the expander icon there. Anyways these are still few pending tasks. Have a look at the screenshot