"Nothing happens when I dock it in a desk dock."
Note the code you have written will only work for a car dock. Hence you have added the word car dock in the category.
To launch an app when in any Dock the following is required
<intent-filter >
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
<category android:name="android.intent.category.DESK_DOCK" />
<category android:name="android.intent.category.CAR_DOCK" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
Note the addition of desk dock