[Plugin: Flutter] Categories Panel Missing

I installed Flutter on my local server and got it working ok, I’m now trying to do the same on my web host. Something weird just happened though.

I created a Write Panel and a few fields for it, so far so good. Noticed I forgot to enable categories as a Standard Panel. Went back and checked it, but it did not take effect, and come to find out the categories panel is missing from the regular post writing page as well now!
I can assign categories from Quick Edit in post manage lists, and everything is fine with categories otherwise. Flutter is even assigning the default category correctly, but I need to sub-categorize these posts. It’s not a deal breaker but, basically going to be a pain unless I can fix this.

I tried deleting the Write Panel, deactivating the plug-in, uninstalling, reinstalling, making a new Write Panel…nothing brought back the Categories Panel.

Any suggestions appreciated. Thanks!