There is only one untouchable area on your application window, the caption bar. This control lets you design the Caption Bar in a very convenient way. You can add a background picture, color gradients, different colors for the background and the caption text, use different fonts, or display your company logo in the caption bar ...
To add more functionality to the caption bar than just filling up the screen, you can add buttons and assign them different pictures for normal, mouseover and pressed state, with tooltips. All the default buttons take care of the new XP themes and their style will automatically change when you change the theme.
You don't need to design your own buttons, if you like you can choose between many different default buttons. In this way you can simulate the original windows min, max and close buttons. Or you can add a checkbox or radio button to the caption that looks exactly like the system default checkbox or radio button.
Use impressive color gradients. You can either use simple 2 color gradients by selecting start and end color and the direction(top-down or left-right) Or you can use extended gradients. These are more colorful and extremely modifiable. To ensure that the gradients are smooth shaded you can select between 3 different halftone modes.