I am aware of this and worked with the snap function. No gaps are visible.
Arcs are indicated as "arcs" in the property window. i have created a closed polyline built from a standard line and an arc today. And it did work.
In a different case it just doesn't, I redrew it severall times. Is it possible to sent this simple example to the Ribbonsoft support in order to check it?
Suggestion: for closed polylines it would be nice to have the area of the form in the properties window, rather tah redrawing it with the area measurement tool.