Snap to Grid 
You can snap items to a grid when moving or resizing objects to make sure they are perfectly aligned.
You are in either Design Manually or Custom Image mode.
You can do the following:
You can activate the alignment of objects to an invisible grid using . This is useful when moving or resizing objects that you want to be spaced proportionally with other objects.
You can move objects in freestyle movement by deselecting . This is useful when you want to offset objects or are in Custom Image mode and you need to overlay hotspots on an imported image.