I couldn't set plot view ranges for plot component (in the attached worksheet). How can i do that?

example worksheet has to draw an ellipse whose center coordinates are determined by two sliders (lef tslider for x, right slider for y). I used following callback function

Do ( xpos = %xPos );
Do ( ypos = %yPos );

Do( %Plot0 = plots[display]( plottools[ellipse]([xpos,ypos],3,4)), view=[-10..110,-10..110],axes=boxed );

When i try setting this task at prompt, it succeeds ...

I want to disable automatic simplification for certain operation(s), for example, instead of usual response