Layout of advancements tab is very glitchy when some further advancements are achieved.

What I expected to happen was...
The format of advancements tab should've been fixed to its own parameters.

What actually happened was...:
Instead, it exceeded its little format and caused a mayhem.

Steps to Reproduce:
1. Open the advancement tab.
2. Use the '/advancement' command to unlock a further advancement (e.g. Sky's the Limit)
3. Once done, open the tab. Bug is reproduced.