Enable Break for specific exception again

Question

I am new to Visual Studio. I\'m programming now, and when I started the program in Visual Studio\'s debugger, it went all OK. When I pressed a button, it focused my code and pop

Answer 1

The pop up you saw was probably an Exception that was later on handled by your code.
In Visual studio you can decide if you want to get a notification every time an exception is thrown (AKA First chance exception) or just when it is not handled.
In order to re-enable the message box, Open the Excetions window (Debug > Exceptions OR Ctrl D, E), and make sure that for Common Language Runtime Exceptions you have the checkboxes marked both for Thrown and for User-Unhandled