Please describe the problem:
When running a dualscreen setup with Xinerama (So that you can move windows between the screens), window placing and sizing does not work as it should.

Part of the desktop is lost on the smaller display:
+---------------+-------------------+
|               |                   |
|               | smaller screen    |
| Larger screen |                   |
|               |-------------------+
|               | Lost desktop area |
+---------------+-------------------+

In this area you can lose your windows: You can place them there but it is off screen so finding them is next to impossible. Also maximizing a window occurs across the whole desktop. Because part of the desktop is obscured so is part of the window. It should instead maximize to fill a single screen instead.
If you have a panel on the bottom it too is lost halfway past the screen, thus taking any applets there with it. The panel should always on the bottom of the _visible_ screen.


Steps to reproduce:
1. Connect 2 monitors to your PC
2. Configure X to use them in xinerama mode, with different resolutions
3. Enjoy general suckiness of window and desktop handling


Actual results:
Windows should not be allowed to be placed outside the visible desktop area.
Windows should maximize to fill a single screen, not the entire desktop.
Panels should reside on the bottom edge of the visible screen, not the virtual.

Expected results:
Generally behaviour should be to behave as if there are two differently sized desktops, as it is in Microsoft Windows, Apple OSX, and other desktop environments such KDE etc.
Screenshot of what MS Windows does: http://www.gigahive.com/sites/dafox/uploads/Screenshot.jpg

Does this happen every time?
Yes

Other information: