Dnspy does not hit breakpoint

[Turkuaz]

Hello all,
I am trying to debug a .NET programme with Dnspy. It stops in some breakpoints, does not stop others.
Then I added below codes however It did not stops but MessageBox shows.

if (Debugger.IsAttached)
			{
				Debugger.Break();
			}
Debugger.Launch();
Debugger.Break();
MessageBox.Show("Select License File");

How can be this?
Because It runs in another thread?
What must I do?

Regards