Run/Rerun a temporal query without events is not displaying msg that minium 2 events are required

log into https://www.i2b2.org/webclient/ as demo user
drag and drop a previous query onto the query name tool box
delete the minimum required 2 events from event selection box by selecting individual event and clicking on 'X' in the group panel box
Go back to population in which events occure selection item and then
run the modified query again
Expected: there should be a msg display that minimum of 2 events are required to run a temporal query
Actual: there is no msg display to the user as to why the query did not run