I’ve set assume_secure_protocol = 1 in the config file as recommended for ssl with a reverse proxy. This seems to set the url protocol correctly everyplace except in the dashboard javascript. The piwik.piwik_url variable in the global js still had “http” for the protocol. For a temporary fix, I put the Piwik::isHttps() check after $this->piwikUrl is set in core/View.
THanks for the report. Can you please create a ticket in trac: dev.piwik.org and post description of your problem, proxy config, and also the patch you put in to fix the issue? very appreciated, thanks!