Clicking on the ppp0 widget at the wrong time (when PPP is coming up or going down, or the ISP isn't responding), or clicking on the color widget, can put usernet into a lost state where it no longer brings PPP up or brings it down, or re-initializes the modem. Colors may change, but modem activity does not. Killing and restarting usernet doesn't clear this. Tried killing X Windows and logging out, then coming back in. That didn't help. Re-booting the host cleared the problem.
*** This bug has been marked as a duplicate of 851 ***