Change look of cursor
Change the cursor in paint brush when painting
Change the cursor in dropper when picking a color
Right ow you want to choose an element, but because you forgot to change the cursor you remove it, or paint it because you do not see in what mode you are.
Most tools will provide better feedback, dedicated cursors and previews with the upcoming, major update (v6.5)
Also change cursor to cross-hairs when using ruller