Chart Layers
    
    The Chart Layers tab contain controls for the display of
    charts.  Some controls are visible only for a specific chart
    type (Histogram, Lines, Dyn Lines, or Matrix).
    
      - On : Enables the layer for display as a chart.
 
- Load (DL) : Enables loading of line-series data from the file
        selected in the overlay.  This is a file property so if the
        file is in more than one layer, the check boxes will have the
        same status.
 
- Settings Wrench :  Launches the Overlay and Map Settings
        Dialog.
 
- Settings Color Bar (H, M): Displays a color bar in the graphics
        window showing distribution of 
 
- Settings Construction : Displays a menu for adding, moving,
        and removing layers.
 
- Setting Color (L): Button with a small color square selects color of a line
      
- Settings Point Offset (L): Offset of text containing point index, x, y.
      
- Setting Mu-Sigma (L): Alter mean/deviation for lines
      
- Settings Matrix (M): Selects view of matrix to the full matrix,
        full with no diagonal, or an lower/upper triangular view.
 
- Settings Opacity (M): Sets the opacity for the matrix in the layer
      
- Width (L): Width of lines
      
- Point (L): Enables display of text for the selected point in a line chart.  Point is selected using the index numerical box or by clicking with mouse in the line.
      
- File : Selects file for the layer.
 
- Yoke : Sets map yoking between layers to a map yoking group
        denoted by a Roman numeral. Navigation between maps of layers in
        the same map yoking group will be yoked (move together). If
        files with differing numbers of maps are set to the same map
        yoking group, a warning will appear before yoking is activated.
        
 
- Index : Selects index of row or map.
 
- All : For histogram, allows one to display a histogram
        containing data from all maps instead of the selected map.
 
- Name : Allows selection of the map by Name.
 
    
    Histogram
    
    Lines
    
    Dyn Lines
    
    Matrix
    