Workaround for ClassNotFoundException

Instead of replacing the method which returns the startup pane, hook the method which gets the pane by String. So in this case when the method receives a String "FEwhat_to_watch" which is usually the case on the first launch, replace it with our own pane string. After that unhook the method, just in case it's needed somewhere else.

I've tested this for the subscription pane only but it worked. It seems like fia.a(String) is only called when launching the app. It's not called when selecting an item from the menu. If you open a web link which opens YT fia.a(String) get's called but it immediately switches to the video/channel/playlist... so the user won't see anything different.

Please test it with other configurations, you know what to test better than me (or release a beta first).
Hopefully I was able to help you, have a nice start in the week!