Question: Maple plotting discontinuous functions

Maple people:

Does anyone know why, if you plot a discontinuous function of one variable, Maple's default behavior is to try to make the function continuous by adding a vertical line segment?  I don't know why anyone would anyone would ever want to graph a function this way.  As far as I know, you have to use the option "discont=true" to remove the vertical segment, which is a hassle.  I consider this to be practically a bug.  I couldn't find a place on Maple's Web site to submit a complaint (this is not really a "support question").   If Maple is installed on a computer, can I change some settings so I don't have to do this?

Related question: if you plot a discontinuous function of two variables, such as Arg(x,y) (the argument of x + yi; I apologize if this is not the exact syntax), you may see a vertical "cliff" which does not belong in the graph.  I do not blame the Maple people for this - it seems like a difficult issue.  Does anyone know a good way to fix such plots?

GS