I have CSS files that are being loaded correctly in FireFox (52.0.1). They are listed in the Style Editor tab, but not in the Network Monitor tab. It doesn't matter if I click All or CSS in the Network Monitor tab, no CSS files show up.
I am including the css files in the <head>
like so:
<link rel="stylesheet" type="text/css" href="https://{path}/css/print.css" media="print">
<link rel="stylesheet" type="text/css" href="https://{path}/plugins/components/jquery-ui/themes/base/all.css" media="all">
I'm assuming they're supposed to show up in the Network Monitor tab considering there is a CSS option, so what gives?
As your screenshot says that there were only 15 requests but you obviously have 8 files in the Network Monitor and an even larger number of CSS files, this looks like a bug in the Firefox DevTools.
I suggest you first try out a new Firefox profile. If it works there, its obviously a bug in your profile. You may track it further down to a specific preference or add-on causing the CSS files not to be listed within the Network Monitor, but in any case you should file a bug.