As described in Searching for specific text, you can use
Attributes → Find Text/Check Symbol... to look
up for specific text. It opens the text search widget at the bottom
of the window. If you click on the option button at the left hand
side of the widget and select the option ‘Check Symbol:’, you’ll
be able to check the symbol page you work with almost the same way as
you would do it with lepton-symcheck though in the interactive mode.
Choosing the option hides widget’s text entry and only two buttons,
‘Find’ and ‘Cancel’, are available then. Clicking on
‘Cancel’ closes the widget. Hit the ‘Find’ button and
lepton-schematic will check your page and open a dialog window with
results of the check. After looking at the issues found and hitting
‘OK’, a new window will be opened where your can select and zoom
on any problematic object on the page.