When more than 26 tabs are made in the advancement gui, only the first 26 can be looked at.

Steps to reproduce:

• Apply the attached data pack Advancement Tabs.zip (it will remove all vanilla advancements, so don't test in a world where you want to keep those)
• use /reload
• Observe the advancement tab has 1 free spot.
• Use /advancement grant @s only advancement_tabs:26
• Observe how the last spot gets filled
• Use /advancement grant @s only advancement_tabs:27
• Observe how no extra tab gets added, still allowing only 26 options.

Expected result:
All tabs would still be able to be inspected, eg with additional arrow buttons to switch to a "next page of tabs".

Actual result:
Only 26 tabs can be inspected at any time.

Original description

The main issue with the advancement screen is that there's no way to view the other tabs if more than 26 show up at once. The remaining ones still unlock advancements and work behind the scenes such as showing up in chat and giving out rewards and toast popups, but you cannot view them or explore the respective tabs in the advancement window.

Included with the bug report is a datapack that has 27 advancement tabs. This is to insure that if the vanilla advancements were disabled, it would at least leave 1 tab out and not visible. With the vanilla datapack, it instead leaves out 6 tabs. Tabs 21 and 22 are labeled, but for the sake of time, I just copied and pasted the other tabs.

(If the attachment doesn't work, a simple datapack with a few dozen tabs works too.)

Do  "/advancement grant @s everything" and open the tab screen, you will notice that all 27 tabs aren't there, despite them showing up in the top right and in chat.

This can be an issue with worlds that have multiple datapacks installed on it, since it's impossible to view them all.