Imported certificate doesn't works at all
Tor Browser 4.0.3 (but I suspect the problem is more general)
With default settings it is impossible to import CA certificate to the tor browser. In order to import a certificate, I unchecked "Don't record browsing history..." option in "security preferences" of the tor button.
But, the imported certificate will not work and not appear in the certificates list if I check the aforementioned option again. I.e., I need to uncheck the option each time I want to connect to the web site using the imported certificate, then check it back.