HI! I'm trying only FreeCad draft by drowing a simple circle or a simple segment . At the end...

HI! I'm trying only FreeCad draft by drowing a simple circle or a simple segment . At the end of the drawing I click and .... the circle or the ligne goes away . Why I am unable to discover the reason. I draw the table, the Lego exercise that works perfectly but with the draft bench it is impossible to work. Could you help me ? Many thanks