Feat Homebrewer Broken

So I was making an altered mobile feat because I learnt that it was good for my favourite class. But when I tried to add a modifier, nothing showed up. Not even the button to begin the process. Can some one help with this.

Are you using a mobile device? It’s probably due to the screen’s narrow display size, turn your phone sideways and more stuff becomes possible.

I've tried that and it didn't work. When u press the plus sign it just turns into minus sign and nothing else happens.