Color Picker

The Color Picker allows you to select the colors used for drawing. In general, the stroke will apply to the border/outline of elements, or to elements that are simply drawn on the image. The fill color is used for filling elements, as well as determining background colors and adding stops to gradients. To change a color, simply click on the corresponding button in the color picker to open the Color Chooser dialog. There is a button between the stroke and fill that will allow you to swap the colors between the two.

Additional Options

The Stroke and Fill buttons both have optional drop down menus that give you the options of removing the fill/stroke, as well as copying one from the other. The Fill button also will let you select a pattern to fill some elements with using the Fill Pattern Selection dialog. Both Stroke and Fill buttons will also allow you to create a gradient color as stroke or fill

Fill Pattern Selection dialog

It is used to select one of the provided patterns or by loading your own image by clicking it's Browse button. The pattern will be applied for filling up elements created as well as text fill.

Stroke/Fill With a Gradient Option

In this option, you can create your own gradient color using the controls available in the colorpicker panel's gradient section