Tools that use the current colour will use the foreground colour on a left click
and the background colour on a right click.
The primitive tools can either be filled or outline. You can select which
behaviour using the 
icon.
Brush Tool
This tool is currently pretty much just like the freehand tool. But what
is of interest is it's properties allow you to set the operator.
The alpha operator combines the brush pixels with the document pixels
in the ratio you specify. 90% would mean mostly the brush and a little of
the document.
Select/Paste Tool
When there is no brush this tool allows you to select a rectangular region
from which a new brush is created. Selecting the tool always clears the
brush.
Once a brush is created this tool alows you to paste the brush on to the
document.
If the "Paste Transparent" option is on when selecting an area as a new
brush any pixel that is the same as the current background colour is made
transparent in the brush. This allows for non-rectangular brushes to be
created.
Eye Dropper Tool
The eyedropper will pick up the colour when you click on the document and
place it in the current foreground colour (left click) or current
background colour (right click)
Magnify Tool
Will center the zoomed view around the location clicked in the normal view.
Text Tool
Is currently still in development. Check in out in the next version.
Flood Fill Tool
Fills with the current colour till the boundry of the colour clicked on.
Freehand Tool
Draws a freehand line in the current colour.
Line/Circle/Ellipse/Square/Rectangle Tools
Draws a primitive in the current colour and fill setting.
Polygon Tool
Draws a polygon in the current colour and fill setting. Place each point
in the polygon using the left mouse button. Use the right mouse button to
complete the object.
