Press "<strong>Continuous drawing</strong>" button on the mode panel to disable automatic switching to previous editing mode after finishing drawing.<br>
Press "<strong>Auto-finish drawing</strong>" button on the mode panel to automatically finish drawing when currently drawn lines and already existing level geometry form a closed shape.<br>
You can use the mode panel or "<strong>Increase Subdivision Level</strong>" and "<strong>Decrease Subdivision Level</strong>" actions to control how detailed the curve is: