Tried several things to get a neat grey box with Maple text in it 
What to do for making this ? 

with(plots,implicitplot3d);with(plots, display3d);
                        [implicitplot3d]

Error, (in with) package plots does not export display3d

------------------------------
As i understand it correct: there is no display3d command in the plots package to find.

Someone is using this display3d in Maple ,but is doesn't matter , because display and display3d  working both the same 
Example : 

p1:=implicitplot3d(x^2+y^2-1=0,x=-2..2,y=-2..2,z=-2..2):
p2:=implicitplot3d(y^2+z^2-1=0,x=-2..2,y=-2..2,z=-2..2):
display({p1,p2});
display3d({p1,p2});
or even

display3DA({p1,p2}); gives 2 3d pics ?

Is there a special display3d command in Maple ?, because (one or more)  plot3d plotstructures with display should show all 3d pics in Maple  ?
 

Something goes wrong with the DE   : de  
Error, unexpected single forward quote

I solved this by converting this : de  to a 2 D Math input 
Something must be chanced
in the configuration settings ? 

Ch05Sec03Prob19.mw

Area of shadow : i have studied one way of solution by hand, but now in Maple ?
Note: for math illustrations : geogebra seems to be wel suited

I know for ordinairy differential equations (ODE) there is a odeadvisor in Maple what shows information about the equation .

What is is possible with a partial differential equations (PDE) package.
Is there a help like for ODE's ?