Feature Request: Ability to extend existing toolbar buttons (like G+)

Hello,

The G+ button is really useful in Wave, and I can see many extensions that 
could do the same kind of thing, to insert all kinds of data, but I see two 
issues with that:
  * there is currently no way (that I know of) to have that kind of floating dialog when clicking a toolbar button, and inserting data in the blip as a result (other than using a gadget and calling a bot) ;
  * it would add a button to the toolbar for each new extension, making the interface more complicated for users every time.

Would it be possible in the future to have plugins for things like the G+ 
button, so extensions can provide new tabs for it for example. Say, in my case, 
a user wants to insert a Bible verse. They could click the G+ button, and have 
a "Bible" tab in addition to "Web", "Images" and "Videos", where the new tab 
would have been added by an extension. This would limit the amount of buttons 
in the toolbar, ease the user experience, and make it possible for devs to use 
functionalities otherwise not available.

Original issue reported on code.google.com by raph...@gmail.com on 30 Jun 2010 at 7:04

dcorking / google-wave-resources

Feature Request: Ability to extend existing toolbar buttons (like G+) #826