title: WPF Default Button command not triggering binding in textbox
body: <p>I have a search screen with some textboxes and a Search button as the default. If I type in a textbox and I CLICK the button, everything's great.  But if I press enter within a text box, the button command fires but the binding on whatever text box I was in does NOT fire and so my criteria doesn't make it to the view model to get filtered on.</p>
  
  <p>I know one fix is to set the bindings on the text boxes to PropertyChanged, but this seems like way overkill.  I might have logic in the viewmodel doing stuff and I don't want that to trigger on every single keystroke.</p>
  
  <p>What I really want is a way for the button itself to either trigger a focus change or somehow trigger binding.  Or to have the textbox trigger binding if focus is lost OR I press enter OR a command is executed from anywhere</p>