1) create a new worksheet
2) add an area region
3) collapse it
4) add a text region below the collapsed region, leaving a wide space.
5) select all (using the "select all" option or simply select the collapsed region and the text region)
6a) move all down a little using the mouse, and then do it again -> the space between the text region decreases progressively; when the text is close enough, goes inside the collapsed area region.
6b) move all up a little using the mouse, and then do it again -> the space between the text region decreases progressively and if you expand the area region, the size become larger at each movement; when the text is close enough, goes inside the collapsed area region. The size increase with absorption happens also if you select only the collapsed area.
Both doesn't happens if you use the up/down keys or if the area is not collapsed.