ai_chat button and back to top button do clash in courses

[lucaboesch]

I honestly do not know where to open this issue best: here or over at https://moodle.org/plugins/theme_boost_union
But my reasoning: Boost Union has been here longer so it's it that should prevail and ai_chat adopt.

Idea: if detected that Boost Union Theme is in user and "Back to top" button option is activated, increase the bottom margin accordingly.
Bonus points if it is achievable that the ai_chat button jumps further up only when scrolling down has occurred and the "Back to top" button appears!

To reproduce: in a Moodle instance install and activate Boost Union and activate backtotopbutton option.

[pkgh]

I fixed that temporarily with this CSS in /admin/settings.php?section=theme_boost_union_look#theme_boost_union_look_scss

#ai_chat_button {
bottom: 8rem !important;
}

(which of course is not the right approach especially if backtotopbutton is not used).

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PS 2026-01-30 17:47:
On Grader report page with the sticky footer, an even higher bottom margin is required,. e.g.:

body#page-grade-report-grader-index #ai_chat_button {
bottom: 12rem !important;
}