Shapes - fill to infinity/-infinity

[omrihaber]

Feature request - i want to be able to add a shape(rect) and be able to specify y value as follows:

1. first value based on y axis
2. second value fill to infinity/-inifnity

afaik today i can either set 'paper' and then both values are precentage based on graph area or 'y' and set both of them as points.