I just installed this plugin (v3.82) in Thunderbird (v31.5.0) I see the plugin in my message pane and am able to navigate to websites. If I click to another tab (Add-ons Manager in this instance) and go back to my main tab that contains ThunderBrowse, my page is blank. Refreshing fixes this, but I was mid form, looking up info to fill. My main issue with the add on is that when I open the preferences for the add-on, I am able to make changes to settings, but the OK button does nothing. I am able to close the dialog, but obviously none of the changes are reflected.