<p>Is there an api to bring the vista side bar to the front (Win+Space) programatically and to do the reverse (send it to the back ground).</p>

Probably using SetWindowPos you can change it to be placed the top / bottom of the z-order or even as the top-most window. You would need to find the handle to the sidebar using FindWindow or an application like WinSpy.
But after that something like.
Sets the window on top, but not top most.
```
```
SetWindowPos(sidebarHandle, HWND_TOP, 0, 0, 0, 0, SWP_NOMOVE | SWP_NORESIZE);
```
```
Sets the window at the bottom.
```
```
SetWindowPos(sidebarHandle, HWND_BOTTOM, 0, 0, 0, 0, SWP_NOMOVE | SWP_NORESIZE);
```
```
This is my best guess on achieving what you asked, hopefully it helps.