I'm having a similar problem, except when I'm pressing backtick nothing happens at all, the __backtick__ div stays empty. similarly, it works fine on the backtick website Chrome 29.0.1547.57 on arch linux.
EDIT: in the interests of clarity, pressing the backtick the first time injects an empty __backtick__ div into the page nothing further happens.
EDIT: Fixed with update to latest chrome. Thanks for the extension, seems great.
Have you updated to the latest version of Chrome? I have never run into the problem you're describing.