Hello, 

Attached is a patch that improves the handling of sharing Cocoa xwidgets. 

The previous implementation of Cocoa xwidgets poorly handled cases where the
user tried to share xwidgets between multiple views (by spamming messages to
*Messages* on every redisplay, and not drawing anything on the second xwidget).
The attached patch fixes this issue by showing a warning label in the place of
 the xwidget view. 

I originally tried to create a bug report with the patch by mailing to
bug-gnu-emacs@gnu.org, but it seems that the report wasn’t created. As such,
I’m sending the patch to the emacs-devel list. How should I proceed with this?

Thanks.

Sungbin Jo