I have been customizing the ijk symbols to place a hat above them as shown in my code below. Although this works well with numerical vectors, I am having trouble getting my custom ijk sybols to show with gradient vectors involving x and y variables. Is this a bug?

See my code below. If I use the number form of $gr it displays my custom i and j, but with the variable vector $gr it does not. Instead all I see is the default script bold i and j.

Code:

Context("Vector2D");

Context()->variables->add( dx=>'Real', dy=>'Real' );

Context()->flags->set( ijk=>1 );$i = "\boldsymbol{\hat{\imath}}";

$j = MODES(

HTML_MathJax => "\boldsymbol{\hat{\jmath}}",

HTML => "\boldsymbol{\hat{\bf{\jmath}}}",

TeX => "\hat{j}");

$k = "\boldsymbol{\hat{k}}";Context()->constants->set(

i => {TeX => $i},

j => {TeX => $j},

k => {TeX => $k});$showPartialCorrectAnswers = 1;

$a = random(2,5,1);

$b = random(2,6,1);

$r = random(-1,1,2);$fx = Compute( "$a*x + $b*e^($r*y)" )->reduce();

$fy = Compute( "$b*x*e^($r*y)" )->reduce();$gr = Vector( $fx, $fy );

# $gr = Vector(3, 6);

$df = Compute( "$fx*dx + $fy*dy" );Context()->texStrings;

TEXT(beginproblem());$grad = MODES(

HTML_MathJax => "{\overset{\scriptstyle\rightharpoonup}{\nabla}}",

HTML => "{\overset{\rightharpoonup}{\vphantom{a}\smash{\nabla}}}",

TeX => "{\overset{\rightharpoonup}{\vphantom{a}\smash{\nabla}}}",

);BEGIN_TEXT

Find the total differential \( dz \) of the function \(f\)

given its gradient is:

\[ $grad f(x,y) = $gr. \]$PAR

\( dz = \) \{ ans_rule(35) \}END_TEXT

Context()->normalStrings;ANS($df->cmp() );

Context()->texStrings;

SOLUTION(EV3(<<'END_SOLUTION'));

$PAR SOLUTION $PARSince \($grad f(x,y) = f_x(x,y) $i + f_y(x,y) $j\) and

\( dz = f_x(x,y)\, dx + f_y(x,y)\,dy\), we have

\[ dz = $df. \]END_SOLUTION

Context()->normalStrings;

Thanks!

Paul