MouseDevice.Capture Method (IInputElement)
Captures mouse events to the specified element.
Assembly: PresentationCore (in PresentationCore.dll)
When an element captures the mouse, it receives mouse input whether the cursor is within its borders
To release mouse capture, call Capture passing null as the element to capture.
If the mouse is captured when a MouseDown or MouseUp event is raised and the input is not going to the element underneath the mouse, PreviewMouseDownOutsideCapturedElement and PreviewMouseUpOutsideCapturedElement are raised first. This enables the captured element a chance to release capture before the MouseDown and MouseUp events are routed.