Demo: draggable bar (for barchart etc)

Define the polygon like this: Polygon(P, Q, (0, y(Q)), (0, y(P))) and then add this as its On Update script to make sure it stays at the same height and can't go negative: SetCoords(P, If(x(P) < 0, 0, x(P)), 1) SetValue(Q, P + (0, 1)) and then make sure "Selection Allowed" is unchecked for 3 of the segments. Also set Algebra -> Increment to eg 1 for Points P and Q (for keyboard control) Try changing the "snap to grid" settings in the style bar. Thanks to Anthony Or for the idea, as shown at #ggbconf2019. Here's a full example to show how it can be used geogebra.org/m/vmbuztsg