message: Cap maximum graph length at 5 seconds.
diff: //$ TODO: Make colors configurable so they're easy to distinguish.
  -//$ TODO: Cap graph length to ~5000
  -
  //$ TODO: Right click on events - popup menu
  // start graph at a specific location
  // find event in graph
  // popup graph tooltip shows events around location you're at?
  +static const int64_t g_max_graph_length = 5000 * MSECS_PER_SEC;
  +
  static SDL_threadID g_main_tid = -1;
  static std::vector< char * > g_log;
  static std::vector< char * > g_thread_log;
  @@ -966,6 +966,9 @@ bool TraceWin::render( class TraceLoader *loader )
  ImGui::SameLine();
  m_do_graph_zoom_out |= ImGui::SmallButton( "Zoom Out" );
  + if ( m_graph_length_ts >= g_max_graph_length )
  + m_do_graph_zoom_out = false;
  +
  if ( m_do_graph_zoom_in || m_do_graph_zoom_out )
  {
  int64_t sign = m_do_graph_zoom_in ? -1 : +1;
  @@ -1657,6 +1660,11 @@ void TraceWin::render_process_graphs()
  m_graph_length_ts = 100;
  m_do_graph_length_ts = true;
  }
  + else if ( m_graph_length_ts > g_max_graph_length )
  + {
  + m_graph_length_ts = 5000 * MSECS_PER_SEC;
  + m_do_graph_length_ts = true;
  + }
  gi.init( m_graph_start_ts + m_tsoffset, m_graph_length_ts );
  gi.eventstart = std::max( ts_to_eventid( gi.ts0 ), m_start_eventid );
  