Why do some applications have `Move to SD card` button disabled? I've just downloaded an app, and I want to move it to SD card. At the application setting, the app has data like this:

Total       ... 10.05MB 
Application ... 9.97MB
Data        ...  80.00KB

Next to 'Clear data' button, 'Move to SD card' button is disabled. Why?
There are some apps that have programming requirements that entail having to be installed on the system SD card.  Think of it as a flag that's set by the app as to whether or not the app can be moved to SD or not.  In this case, it can't be as it would destroy the app's functionality.