Hello.
To have a subVI open its front panel when it executes and close its
front panel when it finished executing you can simply right click on
the subVI in the top-level VI's block diagram, go to "subVI node
setup" and put a checkmark both on "Show front panel when called" and
"Close afterwards if originally closed". Note that this configuration
only affects this instance of the subVI. If you want the subVI to
behave that way always, you can open the subVI, go to File > VI
Properties, go to the "Window Appearance" section, click on
"Customize" and again put a checkmark on both "Show front panel when
called" and "Close afterwards if originally closed". This will open
and close the subVI's front panel every time it is called as a subVI.
