TradeChart shows a fixed 21-bar window. Once a trade is older than that, its entry bar precedes the window and entryIdx goes negative, so the price and trail paths index past the start of series/stopPath and emit NaN coordinates -- the browser then drops both paths entirely, leaving only the horizontal level lines. Clamp the index to the left edge and drop the entry marker when the entry bar is outside the window; the full-width entry line already carries it. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>