The look of the Windows Vista Sidebar is a little drab, and there’s no way to customize it with the default tools in Vista. Thankfully third party developers have stepped up to the plate and created an application that will let you re-theme the sidebar.
Note: After installing and launching this application you will need to restart the Vista sidebar.
When you launch the Windows Sidebar Styler application, it will give you this dialog that gives you a list of all the elements in the theme. You can select the items and see a preview on the right.
The big Play button will apply the style, but first you’ll need to load it by clicking the button to the right for “Load a Windows Sidebar Style”, which will open up a file selection dialog so you can choose from the different themes.
There’s a bunch of themes that come with the application, or you can find more themes at the WinCustomize gallery.
If you click the More button on the dialog, you can even select an option to make the sidebar resizable.
Once you select that option, you can resize the sidebar like any other window. You’ll notice a new option to “Lock” the sidebar, which will prevent resizing once you’ve chosen the size that you want.
Another benefit to this tool is that you can load more powerful gadgets utilizing WPF (Windows Presentation Framework).