In Eclipse open DroidGap.java. Find the function public void onCreate(Bundle savedInstanceState). Find the lines that look like this:

getWindow().setFlags(WindowManager.LayoutParams.FLAG_FORCE_NOT_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FORCE_NOT_FULLSCREEN);

And change them to this:

getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);