When an element captures the mouse, it receives mouse input whether or not the cursor is within its borders. The mouse is typically captured in this manner only during drag-and-drop operations, and retains capture until the drop action of the drag-and-drop operation occurs.
// Mouse.Capture returns an IInputElement.
captureElement = Mouse.Captured;
// Update the Label that displays the element with mouse capture.
lblHasMouseCapture.Content = captureElement.ToString();
Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)