Click on this icon to switch on and off magnetic snap to
horizontal frame edges. When switched on, frames being created will
snap to the horizontal edges of already existing frames, though you
can set a separation between them with the Magnetic frame range
function of the Guidelines module. If the new frame is being created
next to or within an existing frame and is smaller or larger, then it
will be enlarged or reduced respectively as both its top and bottom
edges will snap to the existing frame boundaries. If it is above/below
the existing frame then its top or bottom will snap to the nearest
horizontal frame boundary.
