I'm trying to use the zoom command to focus on some terms in an expression. Strangely enough it only picks out one of the two terms that contain the piece that I want to zoom in on in one case. And it doesn't pick out the only term that fits my criterion in the other case. What am I doing wrong?

Here's my example code. In one case, I tried to zoom in on terms that contain `\delta(g)^{\mu \nu}`

of which there are two but it only returns one of them. In the other case, I tried to zoom in on the lone term containing a `\delta(F)_{\mu \nu}`

but it returns nothing.

```
{ \alpha, \beta, \mu, \nu, \lambda, \kappa, \rho, \sigma, \sigma# }::Indices(total, position=independent).
\partial{#}::PartialDerivative.
{\nabla{#}, \delta{#}}::Derivative.
g_{ \mu \nu }::Metric.
g^{ \mu \nu }::InverseMetric.
g_{ \mu? \nu? }::Symmetric.
g^{ \mu? \nu? }::Symmetric.
g{#}::Depends(\nabla{#}, \partial{#}, \delta{#}).
\delta(g)^{\mu \nu}::Symmetric.
F_{\mu? \nu?}::AntiSymmetric.
F^{\mu? \nu?}::AntiSymmetric.
\delta{F}_{\nu? \rho?}::AntiSymmetric.
F{#}::Depends(\nabla{#}, \partial{#}, \delta{#}).
ex:= L = - \sqrt{g} \frac{1}{4} g^{\mu \alpha} g^{\nu \beta} F_{\alpha \beta} F_{\mu \nu} ;
varyex:= \delta{L}.
substitute(varyex, ex)
product_rule(varyex, repeat=True)
sort_product(varyex, repeat=True)
rename_dummies(varyex)
distribute(varyex, repeat=True)
collect_factors(varyex, repeat=True)
substitute(varyex, $\delta(g) -> - g (g_{\mu \nu} \delta(g)^{\mu \nu})$, repeat=True)
collect_factors(varyex, repeat=True)
meld(_, repeat=True);
zoom(_, $\delta(g)^{\mu? \nu?} Q??$);
unzoom(_)
zoom(_, $\delta(F)_{\mu \nu} Q??$);
unzoom(_)
```