Android Question EditText strange behaviour


Licensed User
Longtime User
I have 2 activity: Main and Second
I have 1 EditText in the Main activity that works just fine.
But if I open the second activity (by StartActivity(Second)) and I click a button in Second activity that brings me back to Main activity (with StartActivity(Main)
the EditText doesn't respond to the touch anymore... it just doesn't open the keyboard!
But if instead of using the button in second activity I use the system back button (the one from Android system) then the EditText works fine...
Am I doing something wrong?
It is not the right way to go back to the Main activity the command StartActivity(Main) ?
Thanks for any help