Interactive tools such as a pointer, drawing, text and shape placement, and others, can be used on the whiteboard over any materials situated on it, even during your screen broadcast.
On the left-hand side, you will find a button that can revert any materials back to their original state at the start of the lecture.
On the right-hand side of the whiteboard toolbar, you will find buttons enabling you to undo or redo the last completed or cancelled operation.