Thanks for your bug report!
I'm really not sure whether binding an action that involves an equal sign to
zoom-in increases usability. Usability crew, any comments? Should ctrl+= be
bound to zoom-in?

I fought long and hard to have the HIG (version 2.0) specify *both*
Before that the HIG actually said to use Ctrl =  which was terrible for many
European users

The problem is that on American (and other) keyboard layouts Ctrl + actually
requires Ctrl  Shift +  where as on many European keyboard layouts the Equals
key is actually quite difficult to get at.  
there is a mental leap happening, users are simply hitting the key with the +
sign on it and not think about it very much

The best solution is to label the menu item Zoom In  Ctrl++ and provide both +
and also  = if possible but if for whatever reason it is impractical to provide
both keybindings then go with Ctrl++ as it is the least worst answer for the
widest possible audience.  

It (having two keybindings for the same thing) is messy but I sincerely believe
it is worth doing, and when it is done right no one will even notice it was ever
an issue.  

Thanks for your explanations Alan.

Created attachment 47143 [details] [review]
Proposed patch (against HEAD).

Thanks for your efforts. The issue will be fixed in the upcoming 2.11 release.