Steps to reproduce:

1. Create or download (see attached file) a resource pack with a copy of assets\minecraft\textures\gui\sprites\widget\button.png.mcmeta from the default files, but with the value of "border" changed from 3 to 100 (or more).
2. Load a world with this pack enabled.
3. Press Escape to open the Game Menu.
4. Notice that instead of opening the menu, the game freezes. Windows will tell you that the app is not responding and you will have to force close it.

For some reason this does not affect the main menu or Options screen, but it does affect the Game Menu (the "pause menu") and the Music & Sounds options.

While changing the border to be half the width of the image (or greater) and not leaving any room for the middle slice may count as misuse of the new "nine_slice" feature, it is bad that the game hangs instead of preventing it in some way.