why [<supports-screens android:anyDensity="true"/>] should be set for robotium explicitly?

As it said in this QnA some functions in robotium required anyDensity to be set as true in the AndroidManifest.xml file. but it said in the android doc that applications that support android 1.6 and higher, it is true by default. then, why should this be set explicitly?

android:anyDensity Indicates whether the application includes resources to accommodate any screen density. For applications that support Android 1.6 (API level 4) and higher, this is "true" by default and you should not set it "false" unless you're absolutely certain that it's necessary for your application to work. The only time it might be necessary to disable this is if you开发者_开发知识库r app directly manipulates bitmaps (see the Supporting Multiple Screens document for more information).