Desktop sidebar is crappy. If you want a real Longhorn sidebar, go here: [link]
It's much better then DS and has a much better look, in beta 3 release it will support skinning! So this skin will 100% included in it since it's longhorn.But if you want to waste your time with DS (not recommended), go ahead and follow these instructions to actually make the Desktop Sidebar look almost like longhorn:
At first run of the sidebar, you'll notice that it's overcrowded with addons, you can close or hide them by clicking the title to hide, or rightclick - close to close.
To configure the sidebar for the perfect longhorn look:
Close all gadgets, leave only Slideshow, Digital Clock and Qucik Launch.
Then go to sidebar options, under general tab, check the run at startup, uncheck the show icon in tray, and Click Don't display details.
In the appearance tab, uncheck the Display capition and panel icons.
Right click slideshow panel, select panel properties, uncheck the show toolbar and progressbar, you can also select a animation, in longhorn it's just "Fade" and Pictures folders.
Now you can Drag and drop the panels to order them correctly. Just click on the panel title and drag it down (up). With clock it may be some troubles. Apply the clocks as last panels.
To add empty space to the sidebar, so you can keep for eg. Clock on bottom always, add a panel called Stack Group.
To add the clock and force it to stay on bottom, right-click on the SIDE of the sidebar (where you'll see the resize arrow) and your clock will be added on bottom. Add two clocks, then go to the upper one and in panel properties set it to analog.
You can hide\show any panel which is over the stack without having to affect the panels which are under it!
To hide the titles of the panels, you can just right click them and uncheck Panel title. or just rename and press Space few times for blank title.
One more thing, to disable the sidebar being on top of windows, in Options and Appearance Tab, set the Z-order to "on Desktop"
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