Fixing Zoom

[hunter19z]

I think it'd be nice to have the option to dynamically update re-zoom when you resize the pane containing the pdf, as is done by overleaf.com. Because, right now, if I double my pane to look closer at the pdf I'm writing, nothing gets bigger and I end up with a lot white-space, and I have to re-fiddle with my zooming and everything.

In short, allow an option to pane re-sizing to be fixed across the x-axis, rather than across the y-axis.