Under Windows 2000, I have configured HKEY_CLASSES_ROOT\news\shell\open\command with the default value of "<path>\Mozilla.exe" -news "%1" In about:config, network.protocol-handler.external.news is not defined (defaults to false), and network.protocols.useSystemDefaults is false. When I enter an autosubscribe news: URL in something other than Mozilla -- such as Start|Run, or clicking the URL in Metapad -- Mozilla opens an "empty" window. This window has no title and no content, just the Moz dragon-head icon in the corner. If the Mozilla mail/news window is not open, a mail/news window opens and the empty window has zero height (other than the titlebar) and is positioned in the upper-left corner of the screen. If the Mozilla mail/news window is already open, a second mail/news window opens (Bug 129574) *and* the empty window is sized to cover the entire screen, but not maximized (similar to a symptom in Bug 168315). This is true for these URLs: news:netscape.public.mozilla.editor (subscribed to) news:netscape.public.mozilla.seamonkey (not subscribed to) news:netscape.public.mozilla.bugzilla (nonexistent) If the registry key is configured without the "-news" command line option: <path>Mozilla.exe "%1" then Mozilla opens a new (unwanted) browser window, but the empty window is not spawned.

Updating a bit for Seamonkey (trunk / 1.5a-0925). (In reply to comment #0) > When I enter an autosubscribe news: URL in something other than Mozilla -- > such as Start|Run, or clicking the URL in Metapad -- Mozilla opens an "empty" > window. This window has no title and no content, just the Moz dragon-head > icon in the corner. I failed to state, originally, that this test is assuming Mozilla was not already running. With Seamonkey, the little window is not a blank any longer; it has a title "Page Load Error" and the standard text in the window. No other window opens; closing the window exits the program. I also note that on restarting Seamonkey immediately, there is a bogus new news account created, called "news" -- xref bug 327885. > If the Mozilla mail/news window is not open, a mail/news window opens and the > empty window has zero height (other than the titlebar) and is positioned in the > upper-left corner of the screen. > > If the Mozilla mail/news window is already open, a second mail/news window > opens (Bug 129574) *and* the empty window is sized to cover the entire > screen, but not maximized (similar to a symptom in Bug 168315). The max-sized-window symptom is not present in Seamonkey. > This is true for these URLs: > news:mozilla.support.thunderbird (subscribed to) > news:mozilla.support.firefox (not subscribed to)