From T152757#2859176
Linter uses jquery.textSelection to highlight the lint errors it finds. If that selection is not in the visible portion of the textbox, in Firefox it scrolls the textbox to make it visible, but that doesn't work in Chromium - it's highlighted, but not visible.
The linter code is as simple as $( '#wpTextbox1' ).focus().textSelection( 'setSelection', { start: location[ 0 ], end: location[ 1 ] } );.