title: webos background image updating problem
body: <p>My application has a preference screen which has a feature for changing the background color or theme. For that, I am using png images with different colors.  When I go to the main screen, I am using some other image depending on the image selected in the preferences.  To do that, I am changing the background image with CSS in the deactivate() method of the preference screen.  In the emulator, it works fine.  When I install the app on the device and check the same case, it shows blank, then it changed the main screen image.</p>
  
  <p>How can I avoid the moment of blank background in the transition from preference screen to main screen?</p>