Fix axis snapping of CollisionPolygon2d's newly created vertex

editor/plugins/abstract_polygon_2d_editor.cpp

@@ -294,9 +294,9 @@ bool AbstractPolygon2DEditor::forward_gui_input(const Ref<InputEvent> &p_event)
 							_commit_action();
 							return true;
 						} else {
-							pre_move_edit = vertices;
 							edited_point = PosVertex(insert.polygon, insert.vertex + 1, xform.affine_inverse().xform(insert.pos));
 							vertices.insert(edited_point.vertex, edited_point.pos);
+							pre_move_edit = vertices;
 							selected_point = Vertex(edited_point.polygon, edited_point.vertex);
 							edge_point = PosVertex();