Cross staff slurs with double curve
While MuseScore supports slurs that cross between staves, it does not allow the slur's curve to change direction midway.
Notice how the upper end points up and the lower end points down, and there is a point of inflection in the middle. This is in contrast with the ordinary slur (above) where both ends point in the same direction.
These double-curved slurs are discussed on p. 321 of Behind Bars, where Gould suggests they may be appropriate when stems for notes on each staff point in opposite directions. However, the screenshot shows they may be appropriate in other situations too.