Stop the windows from taking focus

Thanks to multitasking, I can do something else where some app tries to load. Than there is this app that tries to ask for a password. And that which wants to tell me everything is Ok. And this that pops to say hello. Glad I have adblock plus, or I'd have more windows popping up to tell me something really important. Not only they are not important, they are distracting too. And a security issue when I'm entering a 96 chars password.

How can I disable this annoying ability to steal focus? Sure, child windows should be OVER the main window and not below. But nothing more. They can flash in the taskbar, anything as long as they don't start beeping.