I've got an HTC Desire from a T-Mobile store 3 weeks ago. The ambient light sensor has never worked and it's enabled on the display settings. I went back to the T-Mobile store and they tried a brand new unit. Unfortunately, that one also seem to have the same issue. Then I called the HTC technical support and they say there are no reports on such kind of issue. Is anyone experiencing this problem? If not, does the display brightness get adjusted quickly or slowly? Any help is much appreciated!