feature request: remember subdir across package changes

[minrk]

When I'm using the browser, I'm often traversing dependencies for a specific platform. Each time I change the package name, the subdir list reloads and resets to (usually) linux-64. It would be nice if the subdir value stayed the same (if valid) on package name change. This would be particularly handy when navigating win-64 dependencies, which is always the bottom of the list.

I love this tool so much, thank you for it!