This creates a docked window on the left of the Viewer window containing the list of layers loaded in order of display. This window can be dragged off from being docked and be a separate window. Double click the title bar to re-dock.
Each layer has a tick box next to it. You can turn the display of individual layers on and off using this.
If you right click on a layer, a menu is displayed with options relating to that layer. Some options are common to all layer types:
Zoom to Layer Extent
Changes the zoom of the Viewer to be the extent of this layer
Removes one of more layers from the Viewer. The layers that are selected will be removed.
Moves the layer 'up' in the rendering order - it is painted later and so is 'higher'.
Moves the layer 'down' in the rendering order - it is painted earlier and so is 'lower'.
Move to Top
Makes this layer top most.
Creates a window with the properties of the image/vector as reported by GDAL/OGR.
For Raster Layers
For Raster Layers there is one more option:
Displays the Stretch Window for this image.
For Vector Layers
For vector layers, there are two extra options:
Allows you to select the colour the vector is drawn in
Set Attribute Filter
Allow you to set an attribute filter - only features matching this filter will be shown.