Select objects in Sketch

Hello,
I want to select and delete small objects in my sketch. Your manual says: Drag to the right to select geometries that are fully contained in the selection box.
Does this not work in Sketch? In my example, I only want to delete the small crossed objects that I fully select with the blue selection rectangle. Unfortunately the long lines are also selected and deleted. The small objects are not constrained to the large lines.

Am I doing something wrong?

Wolfgang

Use the trim tool instead? It looks like selecting the nodes at the end of the lines causes the unwanted deletion of the lines?