Rocks'n'Diamonds

I just discovered that when selecting some elements with the "Grab brush" using the middle or right mouse button, what was placed at the brush you grabbed will be replaced by the element selected which was selected earlier by the middle or right mouse button.

This can be used to move elements without copying and then deleting.

Cool, never noticed that...
Seems quite useful... I have to take note of it somewhere

I already have been using this as an "eraser." If I want to move something, I grab the area with the grab brush, middle-click to insert empty space, and move the area to the new location and left-click.