Why is my ui corner gone when I playtest?

[Realgoodguyalways (Real)]

so i a trying to make a simple gui that opens a window when clicked.
normal studio:

you can see two things in this picture:
a: my button looks horrible (pls help me get it to look better if you can)
and b: that i have a ui corner on the text button
while playtesting:

as you can see, while I playtest there is no ui corner, and i want ui corner…

[VegetationBush (FartedWayTooHard)]

You set Archivable to false. Set it to true to have it appear in game.

[Realgoodguyalways (Real)]

Huh, clicking random buttons does have consequences! Actually though, thank you.

Do you happen to have any ideas on how i can make my ui not look like trash? Lol.