@独阳王 Extended UI mod doesn't touch the main page at all, so it shouldn't be able to affect it. More likely that Pokemon mod forgot something in their last update

There is a bug that needs to be reported to you, after this mod is installed with the Pokemon mod, the small flag on the left side of the "pet House" building on the main page will disappear, leaving only a flag pole. (The Pokemon mod changed the flag, the original will not appear)

Might take a while but it would be cool to make the pet selector scrollable as well. With the way it's set up though it might require redoing the pet selector somehow. Just a thought as the amount of possible pets with mods clutters the screen and makes it a little hard to pick them.