How to paint a selection

Let's make a random selection and use an useful trick to fill it with paint.

Open GIMP and create a new document (File, New).

Click here for the how to install GIMP lesson.

Click the Ellipse Select Tool.

Click the Replace the current selection mode.

Draw a circle.

To make a perfect circle, press and hold shift key right after you start drawing the ellipse.

Click the Rectangle Select Tool.

Click Substract from the current selection mode.

And draw a square, just like on on the picture.

To make a square, press and hold shift key right after you start drawing the ellipse.

Click the Paintbrush Tool.

You can change the foreground color if you like.

Select the Circle Fuzzy brush, or any other brush you like.

Now click Edit and Stroke Selection.

Choose Stroke with paint tool and click Stroke.

Click Select and None (Shift+Ctrl+A for the keyboard shortcut).

That's it, your custom selection is painted!