There are three ways to delete elements. The first button is for quickly deleting the last element; it supports consecutive clicks. Each click will quickly delete the last element in a counterclockwise order.
The second button is used to clear the designer desktop, which deletes all elements and restores the initial state.
The third method is the most interesting, allowing you to delete elements at any position. First, press and hold the element you want to delete, then drag it to the trash can icon. Release your hand, and you will find that the element has been deleted.