On some pages the browser slows down considerably and a message pops up, telling me the this plugin is slowing down the page. May be caused by pages containing lots of input fields, but makes it unusable in some administration masks.

Update: Thank you for fixing this issue, I now can definietly recommend using this plugin to integrate the Passwd service into Firefox.

I am unable to log into passwd with the Firefox plug-in. I get an error that the "App's Request is Invalid."