How do I change the color in the Dimensions, Screens, Guides, Frames, and Crosshair tools?

Different aspects of xScope's UI show up on screen in a certain default color. These colors can be changed from xScope's preferences pane. You can open the preferences by going to xScope -> Preferences. Under the tab for each tool, you can adjust what color these tools are and how transparent these aspects are when they appear on-screen.