diff --git a/CLAUDE.md b/CLAUDE.md
index ab2887c..968ff85 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -212,7 +212,7 @@ Every path below exists; keep this list in step with `src/` when adding modules.
     both at half the size in the label grey. Reads the pointer, or the selected
     feature when there is one
   - `AnnotationTables.js` - The three table columns, their headers, count chips
-    and the "Clear all annotations" footer
+    and the "Clear all" footer
   - `icons.js` - The button glyphs, drawn as inline SVG in `currentColor` so
     they follow the button's states as text does. A mode's glyph rides beside
     its word; a view control's replaces it, keeping the word in a visually
diff --git a/docs/Control-Panel.md b/docs/Control-Panel.md
index c2c1edb..0432f89 100644
--- a/docs/Control-Panel.md
+++ b/docs/Control-Panel.md
@@ -187,7 +187,7 @@ dark-on-white one does, which is the whole point of a plate over a halo. It is a
 threaded through the renderers, because selection changes far more often than
 the features do.
 
-The sidebands column carries a footer holding **Clear all annotations**, on
+The sidebands column carries a footer holding **Clear all**, on
 every page. It was trainer-only, on the reasoning that a student's work expires
 overnight anyway — but "it will be gone tomorrow" is no answer to a student who
 has mislabelled a gram and wants to start the exercise again today. Clearing is
diff --git a/docs/Testing-Strategy.md b/docs/Testing-Strategy.md
index 2cf6a5c..8aab8fe 100644
--- a/docs/Testing-Strategy.md
+++ b/docs/Testing-Strategy.md
@@ -69,7 +69,7 @@ tests drive real mouse and keyboard events against a debug page or a fixture in
   speed, pan/zoom (including wheel navigation and clamping), and cross-mode
   integration
 - **Persistence**: trainer/student context detection, save and restore, the
-  student 24-hour expiry, "Clear all annotations", and the warning shown when storage
+  student 24-hour expiry, "Clear all", and the warning shown when storage
   refuses a write
 - **Keyboard and focus**: instance focus, Tab navigation, arrow-key handling
 - **Lifecycle and API hygiene**: the debug-only `__test__*` surface, listener
diff --git a/src/components/AnnotationTables.js b/src/components/AnnotationTables.js
index 38c79cf..c471c85 100644
--- a/src/components/AnnotationTables.js
+++ b/src/components/AnnotationTables.js
@@ -118,7 +118,7 @@ function setCount(container, count) {
 }
 
 /**
- * Put the "Clear all annotations" button at the foot of the sidebands column.
+ * Put the "Clear all" button at the foot of the sidebands column.
  *
  * On every page, trainer and student alike: a student whose annotations expire
  * overnight still wants to start today's exercise again today, and clearing is
@@ -137,7 +137,7 @@ export function mountClearAllButton(instance, onClear) {
   const button = document.createElement('button')
   button.type = 'button'
   button.className = 'gram-frame-clear-btn'
-  button.textContent = 'Clear all annotations'
+  button.textContent = 'Clear all'
   button.title = 'Remove every cross, harmonic set and sideband set'
   button.addEventListener('click', event => {
     event.preventDefault()
diff --git a/src/core/annotationCommit.js b/src/core/annotationCommit.js
index 60e6b5f..2beac16 100644
--- a/src/core/annotationCommit.js
+++ b/src/core/annotationCommit.js
@@ -1,4 +1,5 @@
 import { dispatch, markAnnotationsChanged } from './state.js'
+import { refreshReadoutTarget } from '../components/CursorReadout.js'
 
 /*
  * Its own module rather than a function in `state.js`, because `state.js` sits
@@ -14,7 +15,7 @@ import { dispatch, markAnnotationsChanged } from './state.js'
  *
  * The cadence every annotation change has to perform -- bump the revision so
  * the storage listener notices, refresh the owning panel or table, re-render
- * the persistent overlay, dispatch -- was copy-pasted at sixteen call sites
+ * the persistent overlay, re-read the readout column, dispatch -- was copy-pasted at sixteen call sites
  * (R9-13). Four steps repeated by hand is four chances to forget one, and the
  * one that goes missing silently is the revision bump: everything still looks
  * right on screen and nothing is saved.
@@ -41,5 +42,10 @@ export function commitAnnotationChange(instance, refreshPanel = null, dispatchOp
     instance.featureRenderer.renderAllPersistentFeatures()
   }
 
+  // The readout column reads the selected feature, so it goes stale with it:
+  // without this a dragged harmonic set showed the spacing it had at the press
+  // until it was deselected (issue #344).
+  refreshReadoutTarget(instance)
+
   dispatch(instance, dispatchOptions)
 }
diff --git a/src/core/selectionTarget.js b/src/core/selectionTarget.js
index 0552290..87dde08 100644
--- a/src/core/selectionTarget.js
+++ b/src/core/selectionTarget.js
@@ -25,16 +25,17 @@ import { normalizeMarkerLabel } from '../utils/markerLabel.js'
  * @typedef {Object} SelectionDescription
  * @property {string} label - What to call it: a marker's own label, or its family and position
  * @property {number} time - Where it sits on the time axis, seconds
- * @property {number} freq - The frequency it is about: a marker's own, a
- *   sideband set's fundamental, a harmonic set's spacing
+ * @property {number} freq - The frequency it is about: a marker's own, or a
+ *   pin set's spacing
  */
 
 /**
  * Describe the selected feature, or null when nothing is selected.
  *
  * A marker has a time and a frequency outright. A pin set has an anchor time
- * and, for its frequency, the number that set is *about*: the fundamental an
- * analyst placed for a sideband set, the spacing that defines a harmonic one.
+ * and, for its frequency, its spacing: the number a drag of any member but a
+ * sideband set's origin changes, and the one an analyst is measuring
+ * (issue #344).
  * @param {GramFrame} instance - GramFrame instance
  * @returns {SelectionDescription|null} The selection, or null
  */
@@ -63,5 +64,5 @@ export function describeSelection(instance) {
   }
 
   const set = (sidebands ? sidebands.sidebandSets : []).find(candidate => candidate.id === selection.selectedId)
-  return set ? { label: `Sidebands ${ordinal}`, time: set.anchorTime, freq: set.fundamentalFreq } : null
+  return set ? { label: `Sidebands ${ordinal}`, time: set.anchorTime, freq: set.spacing } : null
 }
diff --git a/tests/harmonics-mode.spec.js b/tests/harmonics-mode.spec.js
index 669fa20..6b81da5 100644
--- a/tests/harmonics-mode.spec.js
+++ b/tests/harmonics-mode.spec.js
@@ -164,6 +164,24 @@ test.describe('Harmonics Mode - creating and adjusting sets by drag', () => {
       expect(spacings[2]).toBeGreaterThan(spacings[1])
     })
 
+    test('the frequency readout shows the live spacing mid-drag, not the spacing at the press (issue #344)', async ({ gramFramePage }) => {
+      await gramFramePage.addHarmonicSet(30, 20)
+      const line = await gramFramePage.page.locator('.gram-frame-harmonic-line').first().boundingBox()
+      if (!line) throw new Error('no harmonic line was rendered to drag')
+      const readout = gramFramePage.freqLED.locator('.gram-frame-led-value')
+
+      await gramFramePage.page.mouse.move(line.x + line.width / 2, line.y + line.height / 2)
+      await gramFramePage.page.mouse.down()
+      await gramFramePage.page.mouse.move(line.x + line.width / 2 + 80, line.y + line.height / 2, { steps: 4 })
+
+      // Read while the button is still down: the release is not what refreshes it.
+      const spacing = (await gramFramePage.getState()).harmonics.harmonicSets[0].spacing
+      expect(spacing, 'the drag changed the spacing').not.toBeCloseTo(20, 1)
+      await expect(readout).toHaveText(spacing.toFixed(2))
+
+      await gramFramePage.page.mouse.up()
+    })
+
     test('dragging an existing set re-spaces it', async ({ gramFramePage }) => {
       // Created through the helper, so the starting spacing is exact and the
       // change below is measured against a known number.
diff --git a/tests/sideband-mode.spec.js b/tests/sideband-mode.spec.js
index 52bd9e7..40e82cc 100644
--- a/tests/sideband-mode.spec.js
+++ b/tests/sideband-mode.spec.js
@@ -133,6 +133,23 @@ test.describe('Sidebands mode', () => {
     expect(updated.fundamentalFreq).toBeCloseTo(50, 5)
   })
 
+  test('the frequency readout shows the live spacing mid-drag, not the fundamental (issue #344)', async ({ gramFramePage }) => {
+    await gramFramePage.addSidebandSet(30, 50, 10)
+    const readout = gramFramePage.freqLED.locator('.gram-frame-led-value')
+
+    // Mid-gesture: no onSetDragEnd, so nothing but the drag itself refreshes it.
+    await gramFramePage.page.evaluate(() => {
+      // @ts-ignore - test-only global
+      const instance = window.GramFrame.__test__getInstances()[0]
+      const sideband = /** @type {any} */ (instance.modes['sideband'])
+      const target = sideband.findSetTarget({ freq: 60, time: 30 })
+      sideband.onSetDragStart(target)
+      sideband.onSetDragUpdate(target, { freq: 70, time: 30 }, { freq: 60, time: 30 })
+    })
+
+    await expect(readout).toHaveText('20.00')
+  })
+
   test('dragging the fundamental moves the origin and leaves the spacing alone', async ({ gramFramePage }) => {
     const setId = await gramFramePage.addSidebandSet(30, 50, 10)