from user voice request.
green dot marking the current time for parametric plots
In a PlotSelectionOverTime filter, the resulting 2D plot can be shown as a function y = y( timestep ). This is the default, and by default a very handy vertical green line marks the current timestep.
The plot can also show parametric graphs, where (x,y) is plotted, and x = x( timestep) as well as y = y( timestep ).
In this latter case, I would like to see a green dot marking the (x,y) of the current timestep.