The appearance of the main keyboard window can now be modified by choosing a colour theme. A colour theme affects all elements of the main keyboard window:
  • Background colour
  • Text colour
  • Key colour
The key colour is specified by twelve colours and three choices of gradient style. A key can be normal, dead key or selected (for swap or showing a found key stroke), and can be either up or down for each of these. For each of the six possible combinations, you choose an inner colour and an outer colour and a gradient style. For a radial gradient, the inner colour is the colour at the centre of the key, and the outer colour is at the corners. For a linear gradient, the outer colour is at the top, and the inner colour is at the bottom. For the style without a gradient, the inner colour is solid for the key, with a 2 pixel border of the outer colour.

Colour themes can be modified, saved, or replaced by using the Colour Theme submenu of the View menu. Colour themes are saved in a file called ColourThemes.plist, stored in a folder called Ukelele inside the user's Preferences folder. This file is an XML property list, and can be edited with a text editor or any program that can handle XML and/or property lists.