This is still pretty weird, but ok.  I'm assuming that m_ChannelName is an array of strings (if it is a TCHAR array or a LPCTSTR array then this probably won't work reliably), and that if the 0th plot pref is the same as the 1st plot pref, you're assuming that things haven't been inited yet.

A better way to do this would be something like
static bool fInitedPlotPrefs = false;
if(!fInitedPlotPrefs)
{
  InitPlotPrefs(hWnd,lParam);
  fInitedPlotPrefs = true;
}