Hi,
as you probably noticed, extensions in chromium Linux moved to "Browser Action", and all old extensions wont work anymore.
In the near future also other version of Chrome (Windows and Mac OS) will be affected and will make use of Browser Action.
Some other extension has been already migrated and you may need to migrate you extension as well.
You can have a look here for details:
http://groups.google.com/group/chromium ... e1557d948b
and here:
http://code.google.com/p/chromium/issue ... l?id=25801
cheers
Massimiliano