|3.4 Stroke and fill colors|
Path objects can have two different colors, one for the boundary and one for the interior of the object. The Postscript/PDF terms stroke and fill are used to denote these two colors. Stroke and fill color can be selected independently in the Properties window. Imagine preparing a drawing by hand, using a pen and black ink. What Ipe draws in its stroke color is what you would stroke in black ink with your pen. Probably you would not use your pen to fill objects, but you would use a brush, and maybe even a different kind of paint like water color. Well, the fill color is Ipe's "brush".
When you create a path object, you'll have to tell Ipe whether you want it stroked, filled, or both. This is set in the Path properties field. Clicking near the right end of the field will cycle through the three modes "stroked", "stroked & filled", and "filled." You can also use the context menu of the path properties field.
Text objects and arrows only use the stroke color, even for the filled arrows. You would also use a pen for these details, not the brush.
The mark shapes "disk" and "square" also use only the stroke color. You can make bicolored marks using the mark shapes "fdisk" and "fsquare".