Keyboard short-cut: Alt, E, G.
Mouse short-cut: 
Changes the default color of lines, polygons, and text; changes the default text font. The following dialog box will appear:
To change the font used by text objects, click on Change Font. To change the color of lines and of the edges of polygons, click on the Color button under Lines, choose a color, and click OK. To change the thickness of lines and the edges of polygons, click in the white box next to Thickness and enter a new thickness or change the thickness by clicking on the arrows. To change the fill color of polygons, click on the Color button under Fill, choose a color, and click OK.