Each half of a keyframe glyph had a 1 px near-black border, so keys
that overlap read as a tangle of borders. Keys are now flat, as in
After Effects: each half is filled and edged in the key's own colour
(the hairline closes the seam between the halves), so overlapping keys
read as one shape. The Light theme's keyframe grey is darker so
unselected keys still stand out on its light time graph without the
border.
Test: keyframes_are_drawn_without_a_dark_outline (icons).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
