Bug 1: cursor slider started at tMin (no data in 60s window at start of data). Fix: start slider at tMax so trail window covers the last trailMs of actual data. Feature 2 (Alexandre Larribau): setupSyncedZoom() propagates xaxis.range to all sibling charts on plotly_relayout, with _syncing guard vs infinite loop. Applied to global charts (depth/PWM/USBL), USV tab, and AUV tab independently. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>