All colors used can be found to the right of the main window.
To select a color, open the “Color selection” menu item to the right of the main view, click on the down arrow, and then on “Open color selection.” Alternatively, double-click in the “Stroke” field to call up the color palette. Below the palette, you can see which color you are currently using and which new color you have selected. All colors used can be found to the right of the main window.