The spectrum passband overlay is drawn one-sided per mode, but DIG was hardcoded to upper sideband — so switching the DIG sideband (or tuning DIG/Auto across 10 MHz) left the overlay on the wrong side of the carrier even though the backend had flipped the demodulator. Resolve the DIG overlay direction from the current sideband policy and dial frequency, mirroring the backend: usb → upper, lsb → lower, auto → upper at or above 10 MHz and lower below. The overlay repaints immediately on a policy change (optimistically on the selector, and on confirmed filter state) and tracks frequency as it already did. Non-SDR backends keep the historical upper-sideband overlay. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01UiK871ht2uPFBHtMbxy3wD Signed-off-by: Stan Grams <sjg@haxx.space>