Thanks for the link, Saurabh, but I don't think it would fix this particular issue as the user isn't brought to a Firefox error page, but one created by the proxy server. To fix this bug, the browser must know in advance that it isn't a proper URL (i.e., doesn't end in ".com" or any other TLD, etc.) and that it should go ahead and send it to the default search engine instead of the proxy server, just the way it does with multi-word searches.
The problem seems to be that Firefox is just assuming that any single word typed into the Address Bar is a URL to be sent to the proxy, instead of checking it first.
Thanks for the link, Saurabh, but I don't think it would fix this particular issue as the user isn't brought to a Firefox error page, but one created by the proxy server. To fix this bug, the browser must know in advance that it isn't a proper URL (i.e., doesn't end in ".com" or any other TLD, etc.) and that it should go ahead and send it to the default search engine instead of the proxy server, just the way it does with multi-word searches.
The problem seems to be that Firefox is just assuming that any single word typed into the Address Bar is a URL to be sent to the proxy, instead of checking it first.