To pause the execution of a VI at any subVI, node, or wire, click the object with the Breakpoint tool, then run the VI.
To temporarily stop the execution of your VI or to insert a probe, click the Pause button in the toolbar.
To edit a VI set to run when opened, break one of its subVIs. The VI opens in edit mode, because it cannot run with a broken subVI. If the VI has no subVIs, place it into the block diagram of a new VI and double-click.
When a subVI is paused, click the Call Chain pull-down menu located on the block diagram toolbar to list all the callers from the top-level VI down to the opened subVI.