Copied from WP:VPT on en.WP: The tooltip for reference [a] in en:Clearing_the_neighbourhood#Margot's_Π is too narrow to accommodate the equations.
Topic on Talk:Reference Tooltips
Appearance
.rt-tooltip
has a max-width: 350px;
. Would require some additional code to check what the overflow is and then overwrite the max-width value. How about just adding word breaks inside the math equations?
.rt-tooltip img { max-width: 100%; }
would also solve this (for when people are using the default image renderer and not MathML)