Stop Screen Switching

How can I stop screen switching after clicking a button?

Instead of stopping screen switching, just don't switch screen ...

Screenshot (120)
Screenshot (121)
But I made the app in such a way in that I have to switch the screen. But I want that when I press Screen.BackPressed button after clicking Save button in just 1-2 seconds when we have on Current Screen not on Screen2, then it stops switching to another screen.
Screenshot (119)
And also if I click on "No, stay here" then according to above case, I want to switch on Screen2.

set Clock.TimerEnabled to false
Taifun

This happened with me a lot of times.
Clock should be disabled else it would run again and again forever.

I have already disabled the clock. Check the second image.

Where I have to set Clock.TimerEnabled to false?

try the Screen.BackPressed event
Taifun

Okay and also I want that when I press Screen.BackPressed button after clicking Save button in just 1-2 seconds and after that if I choose "No, stay here" on notifier then I want to switch on Screen2.