Android : Dialog with EditText strange behaviour of SoftKeyboard

I have a layout with some EditText to let the user input some data. In the same Activity the user can add items to a list and for that i show a DialogFragment with an EditText. When the Dialog is created and the user taps into the EditText of the Dialog to make the keyboard appear the whole view of my activity gets scrolled because the EditText of my Activity and not of my Dialog is requesting the focus. Thats really annoying.

How can i fix that? When i call a dialog i dont want the calling activity to get focus.