If I let Maple be running on the computer for a while, maybe a day or 2 or so, I almost certainly get a change of several

characters. See my favourite palette:

As you can see the eternity sign e.g changes to a big N. If I rerun the worksheet everything works ok except for the change of characters.

Not seen above: :=  changes to d

Remedy?

If I make a single plot it will always be located in the centre of the worksheet. Is there an option to place it at the left border?

I don't like the font times new roman in Math 2D input. Can't find where to set a font anywhere except in the head at a new worksheet. But that alters immediately after executing a command. There should be a place in preferences at least to do a persistent change of font.

What's wrong here?

restart; with(PDEtools); PDE2 := diff(u(x, y, t), t$2) = diff(u(x, y, t), x$2)+diff(u(x, y, t), y$2); IBC2s := u(x, 0, t) = 0, u(x, 2, t) = 0, u(0, y, t) = 0, u(4, y, t) = 0, u(x, y, 0) = (.1*(-x^2+4*x))*(-y^2+2*y), (D[3](u))(x, y, 0) = 0; Sol2 := pdsolve({IBC2s, PDE2}); build(Sol2);

Error, invalid input: PDEtools:-build uses a 1st argument, ANS (of type {`=`, PDESolStruc}), which is mis
 

PDE := diff(u(x, t), t$2) = (1/16)*(diff(u(x, t), x$2))-(1/5)*(diff(u(x, t), t)); IBCs := u(x, 0) = x*(1-(1/2)*x), (D[2](u))(x, 0) = x*(1-(1/2)*x), u(0, t) = 0, (D[1](u))(1, t) = 0; Sol := pdsolve({IBCs, PDE}, HINT = f(x)*g(t)); Sol := subs(op([2, 2, 1], Sol) = n, Sol)

I thought that the addition of HINT wolud help but no.

The numeric solution gives the right answer but the analytical gives way too small numbers and wrong shape.