Why is the Clear button used in the MoonBot terminal in the Pencil button menu in the drawing elements menu?

: Interface configuration

In the MoonBot terminal, after clicking on the “Pencil” button, buttons with different drawing elements open. Each menu has a Clear button, which, when pressed, clears all the drawing elements in the menu where it is located. That is, if, for example, on the chart of a coin that is open to full screen, you need to clear all horizontal lines-levels (Price Line), then you must first click on the Price Line icon and then click on the Clear button in its menu.