title: What does it mean to "Capture the mouse" in WPF?
body: <p>On <code>System.Windows.UIElement</code> there is a <code>CaptureMouse()</code> and a paired <code>ReleaseMouseCapture()</code> method.  In this <a href="http://msdn.microsoft.com/en-us/library/bb295243.aspx" rel="noreferrer">WPF DragDrop</a> sample they call CaptureMouse on MouseDown and release it on MouseUp.  The <a href="http://msdn.microsoft.com/en-us/library/system.windows.uielement.capturemouse.aspx" rel="noreferrer">documentation in MSDN</a> is about as useless as it comes - "CaptureMouse -> Captures the mouse."</p>
  
  <p>In my head before trying it I assumed that it somehow locked the mouse inside the UIElement bounds, but that's clearly not the case when I try it.  From experimenting, it seems to have something to do with responding to events when the mouse is outside of the UIElement, but not wanting to be a <a href="http://en.wikipedia.org/wiki/Cargo_cult_programming" rel="noreferrer">cargo cult programmer</a> I don't want to just use it because the example does, I'd like an authoritative description of what it means.</p>