To open and edit a subVI, use the Operating or Positioning tool to double-click the subVI on the block diagram. LabVIEW displays the front panel of the subVI. To display the block diagram and front panel of the subVI, press the <Ctrl> key and use the Operating or Positioning tool to double-click the subVI on the block diagram. (macOS) Press the <Option> key. (Linux) Press the <Alt> key.