To delete one sketch-element - and you can select one sketch-element.

1.Click the sketch-element in the graphics-area

2. Click the Delete key on your keyboard

To delete ONE sketch-element, but you select more than one sketch-element:

1.Click the sketch-element in the graphics-area

The element shows in the Selection-Window.

2.Right-click the sketch-element you want to delete in the Selection-Window

A shortcut menu shows next to your pointer:

3.Click Delete element in the shortcut menu

To delete multiple sketch-elements:

1.Drag a window to select multiple sketch-elements in the graphics-area

2.Click the Delete key on your keyboard