While the Diamond is no doubt a very attractive and functional device, HTC has in some ways taken away functionality which Windows Mobile users have taken for granted for many years now. An example of one of these is memory card expansion, but a more interesting example is the ability to rotate the screen, the option for which has been there since WM2003SE.
When HTC was asked about this they claimed they had designed the product to be used single handed, and that this was impossible in landscape mode. A more likely explanation however is that they could only design their TouchFlo3D UI to work in portrait mode, and that the design challenge would have redoubled if they were to support landscape mode too.
However, this being Windows Mobile, there is no end to the efforts of the community to fix what the OEM has managed to mess up. Intrepid Diamond users over at XDA-Developers.com have managed to come up with the correct registry keys to restore the screen rotation control panel, meaning any app can now be viewed both in portrait and landscape mode. Any app that is except the TouchFlo UI, which reverts the device to portrait mode when the Home button is pressed.
The entries which need to be changed with a registry editor are:
HKeyLocalMachine/System/GDI/Rotation change the “HideOrientationUI” from 1 to 0
HKeyLocalMachine/System/GDI/Rotation change the “LandscapeFixed” from 1 to 0
Unfortunately you still have to go to the control panel to affect this change every time you need to rotate the screen – the accelerometer only work in certain apps, but I am sure the happy people at XDA-Developers wont rest until automatic screen rotation in every application is possible.