Android Eclipse tips: switch between Automatic and manual target modes

In Eclipse and ADT, you can select launching your app automatically select suitable AVD/device, or manually select.

By default, a run configuration uses the automatic target mode in order to select an AVD/device. If your run configuration uses manual mode, then the "device chooser" is presented every time that your application is run, so that you can select which AVD/device to use.
~ http://developer.android.com/tools/building/building-eclipse.html#RunConfig

To set Run Configuration:

• Right click your project -> Run As -> Run Configurations...
  
  
• or, Click the arrow (downward) beside the Play button (green arrow) on the top menu -> Run Configurations...
  

In Run Configuration Dialog, select your project under Android Application on the left, select Target, then select your expect Deployment Target Selection Mode.