@Override
	public boolean isColoringBackground() {
		return colorBackground;
	}
Get the tooltip for the marker at the specified index and address

@param addr address of item to navigate to
@param x x location of cursor
@param y y location of cursor

@return tool tip string, null if no tool tip
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/marker/MarkerSetImpl.java