diff --git a/indicator_pane.go b/indicator_pane.go
new file mode 100644
index 0000000..547d864
--- /dev/null
+++ b/indicator_pane.go
@@ -0,0 +1,220 @@
+package mujica
+
+import (
+	"fmt"
+	"log/slog"
+	"math"
+	"strings"
+
+	"github.com/egoist/mygo/ui"
+
+	"mujicaui/icons"
+	"mujicaui/internal"
+	"mujicaui/theme"
+)
+
+// IndicatorPaneSpec is one lower pane: MACD, RSI, KDJ or OBV.
+type IndicatorPaneSpec struct {
+	Kind IndicatorKind
+	// Params nil uses the kind's defaults.
+	Params []float64
+}
+
+// IndicatorPanes is the caller-held stack of panes and their height shares.
+type IndicatorPanes struct {
+	Panes []IndicatorPaneSpec
+	// Sizes are the panes' height shares; they reset to equal when the pane count changes.
+	Sizes []float32
+}
+
+// IndicatorPaneOptions configure an IndicatorPane.
+type IndicatorPaneOptions struct {
+	// Height is the whole stack's height; zero is 140 per pane.
+	Height float32
+	// Label prefixes each pane's accessible name, as the symbol.
+	Label    string
+	Disabled bool
+}
+
+// IndicatorPaneResult reports the stack's events.
+type IndicatorPaneResult struct {
+	Element *ui.Element
+	// Removed is the index of the pane closed this frame, -1 for none.
+	Removed int
+	// Resized reports finished height changes, for saving.
+	Resized bool
+}
+
+// IndicatorPane stacks indicator panes under a price chart, sharing its view; dividers between them resize.
+func IndicatorPane(c *ui.Context, candles []Candle, view *MarketView, panes *IndicatorPanes, opts IndicatorPaneOptions) IndicatorPaneResult {
+	if view == nil || panes == nil {
+		panic("mujica: IndicatorPane needs a view and panes")
+	}
+	res := IndicatorPaneResult{Removed: -1}
+	n := len(panes.Panes)
+	for _, p := range panes.Panes {
+		if _ = p.Kind.String(); indicatorInfo[p.Kind].overlay {
+			panic(fmt.Sprintf("mujica: %v is an overlay, not a pane indicator", p.Kind))
+		}
+		indicatorParams(p.Kind, p.Params)
+	}
+	if n == 0 {
+		res.Element = ui.Column(c)
+		return res
+	}
+	if len(panes.Sizes) != n {
+		panes.Sizes = nil
+	}
+	h := opts.Height
+	if h == 0 {
+		h = 140 * float32(n)
+	}
+	build := func(i int) func() {
+		return func() {
+			col := ui.Column(c).Fill().MinHeight(0)
+			b := col.Bounds()
+			internal.Remeasure(c, col, b.W, b.H)
+			u := Density(c).Unit()
+			// The plot takes what the title, legend and readout rows leave.
+			plotH := max(40, b.H-2*theme.MinHitSize-u*12)
+			col.Children(func() {
+				if indicatorPaneOne(c, candles, view, panes.Panes[i], opts, plotH) {
+					res.Removed = i
+				}
+			})
+		}
+	}
+	box := ui.Column(c).Height(h).FillWidth().Disabled(opts.Disabled)
+	box.Children(func() {
+		if n == 1 {
+			build(0)()
+			return
+		}
+		list := make([]ResizablePanel, n)
+		for i, p := range panes.Panes {
+			list[i] = ResizablePanel{Label: indicatorName(p.Kind, indicatorParams(p.Kind, p.Params)), Min: 60, Build: build(i)}
+		}
+		r := ResizablePanelGroup(c, &panes.Sizes, list, ResizablePanelGroupOptions{Vertical: true})
+		r.Element.Fill()
+		res.Resized = r.Committed
+	})
+	if res.Removed >= 0 {
+		slog.Debug("mujica: indicator_pane removed", "kind", panes.Panes[res.Removed].Kind)
+		panes.Panes = append(panes.Panes[:res.Removed:res.Removed], panes.Panes[res.Removed+1:]...)
+		panes.Sizes = nil
+		c.Invalidate()
+	}
+	res.Element = box
+	return res
+}
+
+// indicatorPaneOne draws one pane's lines over the view's window; it reports the close button.
+func indicatorPaneOne(c *ui.Context, candles []Candle, view *MarketView, spec IndicatorPaneSpec, opts IndicatorPaneOptions, height float32) bool {
+	k := Tokens(c)
+	params := indicatorParams(spec.Kind, spec.Params)
+	name := indicatorName(spec.Kind, params)
+	closed := false
+	ui.Row(c).AlignItems(ui.Center).Gap(Density(c).Unit()).Children(func() {
+		ui.Text(c, name).FontSize(FontSize(c, theme.CaptionSize)).FontWeight(600).TextColor(k.Text).Grow(1)
+		closed = iconAction(c, icons.Must("x"), fmt.Sprintf(msg(c, "indicator_pane.remove"), name)).Clicked()
+	})
+	label := strings.TrimSpace(opts.Label + " " + name)
+	ch := newChart(c, ChartFrame{Label: label, Height: height})
+	series := chartMemo(ch, "series", fmt.Sprintf("%s|%v|%v", chartID(candles), spec.Kind, params), func() []ChartSeries {
+		marketCheckCandles(candles)
+		return indicatorSeries(spec.Kind, params, candles)
+	})
+	m := &mktCore{c: c, k: k, ch: ch, candles: candles, view: view}
+	m.window()
+	pal := internal.Palette(k)
+	lines := make([]mktLine, len(series))
+	keys := make([]chartKey, len(series))
+	for i, s := range series {
+		lines[i] = mktLine{name: s.Name, values: s.Values, color: pal[(i+1)%len(pal)], shape: i}
+		keys[i] = chartKey{Name: s.Name, Color: lines[i].color, Shape: i}
+	}
+	yr := chartMemo(ch, "y", [3]any{chartID(candles), m.from, m.to}, func() [2]float64 {
+		lo, hi := math.Inf(1), math.Inf(-1)
+		for _, l := range lines {
+			for i := m.from; i < m.to; i++ {
+				if v := l.values[i]; !math.IsNaN(v) {
+					lo, hi = min(lo, v), max(hi, v)
+				}
+			}
+		}
+		if spec.Kind == IndicatorRSI {
+			lo, hi = 0, 100
+		}
+		return [2]float64{lo, hi}
+	})
+	lo, hi := yr[0], yr[1]
+	spec2 := chartSpec{n: len(candles), keys: keys}
+	if m.to <= m.from || math.IsInf(lo, 0) {
+		spec2.n = 0
+	}
+	m.lo, m.hi = lo, hi
+	spec2.pick = func(r ui.Rect, x, y float32) int {
+		g := m.paneGeom(r)
+		if !g.plot.Contains(x, y) {
+			return -1
+		}
+		return g.index(m, x)
+	}
+	spec2.readout = func(i int) string {
+		parts := []string{candles[i].Time.Format("2006-01-02 15:04")}
+		for _, l := range lines {
+			parts = append(parts, l.name+" "+chartValue(c, l.values[i], func(v float64) string { return fmt.Sprintf("%.2f", v) }))
+		}
+		return strings.Join(parts, " · ")
+	}
+	spec2.draw = func(p *ui.Painter, r ui.Rect, active int) {
+		g := m.paneGeom(r)
+		size := FontSize(c, theme.CaptionSize)
+		internal.AxisY(p, g.plot, g.ys, g.ticks, func(v float64) string { return volumeShort(v, g.step) }, size, k)
+		p.Clip(g.plot, 0, func() {
+			for i, l := range lines {
+				if spec.Kind == IndicatorMACD && i == 2 {
+					indicatorPaneBars(p, g, m, l.values, c)
+					continue
+				}
+				mktPaintLine(p, g, m, l.values, l.color, i)
+			}
+		})
+		if active >= m.from && active < m.to {
+			x := internal.Snap(p, g.x(m, active))
+			p.Line(x, g.plot.Y, x, g.plot.Y+g.plot.H, 1, k.TextMuted)
+		}
+	}
+	ch.build(spec2)
+	return closed && !ch.res.Element.IsDisabled()
+}
+
+// paneGeom is geom without the time axis, for lower panes.
+func (m *mktCore) paneGeom(r ui.Rect) mktGeom {
+	plot := chartInset(r, 60, 4)
+	lo, hi, step := internal.Nice(m.lo, m.hi, 2)
+	return mktGeom{plot: plot, band: internal.Band{N: m.to - m.from, R0: plot.X, R1: plot.X + plot.W, Pad: 0.3},
+		ys: internal.Linear{D0: lo, D1: hi, R0: float64(plot.Y + plot.H), R1: float64(plot.Y)}, ticks: internal.Ticks(lo, hi, step), step: step}
+}
+
+// indicatorPaneBars draws MACD's histogram: hollow bars above zero, filled below.
+func indicatorPaneBars(p *ui.Painter, g mktGeom, m *mktCore, vals []float64, c *ui.Context) {
+	k := Tokens(c)
+	zero := g.ys.Map(0)
+	w := max(1, g.band.Width())
+	for i := m.from; i < m.to; i++ {
+		v := vals[i]
+		if math.IsNaN(v) {
+			continue
+		}
+		y := g.ys.Map(v)
+		x := internal.Snap(p, g.x(m, i))
+		bar := ui.Rect{X: x - w/2, Y: min(y, zero), W: w, H: max(1, float32(math.Abs(float64(y-zero))))}
+		if v >= 0 && w >= 3 {
+			p.Fill(bar, k.Surface, 0)
+			p.Stroke(bar, trendColor(c, 1), 0, 1)
+		} else {
+			p.Fill(bar, trendColor(c, trendSign(v)), 0)
+		}
+	}
+}
diff --git a/indicator_pane_test.go b/indicator_pane_test.go
new file mode 100644
index 0000000..332e2ac
--- /dev/null
+++ b/indicator_pane_test.go
@@ -0,0 +1,65 @@
+package mujica
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/egoist/mygo/ui"
+)
+
+func TestIndicatorPaneStackReadAndRemove(t *testing.T) {
+	candles := sampleCandles(300)
+	view := MarketView{Count: 80}
+	panes := IndicatorPanes{Panes: []IndicatorPaneSpec{{Kind: IndicatorMACD}, {Kind: IndicatorRSI, Params: []float64{6}}}}
+	removed := -1
+	tt := ui.NewTester(func(c *ui.Context) {
+		Use(c, Settings{})
+		if r := IndicatorPane(c, candles, &view, &panes, IndicatorPaneOptions{Label: "BTC"}); r.Removed >= 0 {
+			removed = r.Removed
+		}
+	}, 800, 500)
+	tt.Frame()
+	if !tt.HasText("MACD(12,26,9)") || !tt.HasText("RSI(6)") || len(panes.Sizes) != 2 {
+		t.Fatalf("texts %q sizes %v", tt.Texts(), panes.Sizes)
+	}
+	tt.Key(0, ui.KeyTab) // remove MACD
+	tt.Key(0, ui.KeyTab) // MACD plot
+	tt.Key(0, ui.KeyEnd)
+	found := false
+	for _, s := range tt.Texts() {
+		found = found || strings.Contains(s, "DIF ") && strings.Contains(s, "DEA ")
+	}
+	if !found {
+		t.Fatalf("MACD readout missing: %q", tt.Texts())
+	}
+	if err := tt.Click("Remove MACD(12,26,9)"); err != nil {
+		t.Fatal(err)
+	}
+	if len(panes.Panes) != 1 || panes.Panes[0].Kind != IndicatorRSI || removed != 0 {
+		t.Fatalf("after remove %+v (%d)", panes.Panes, removed)
+	}
+	for name, p := range map[string]IndicatorPanes{
+		"overlay kind": {Panes: []IndicatorPaneSpec{{Kind: IndicatorMA}}},
+		"bad params":   {Panes: []IndicatorPaneSpec{{Kind: IndicatorRSI, Params: []float64{1, 2}}}},
+	} {
+		func() {
+			defer func() {
+				if recover() == nil {
+					t.Errorf("%s: no panic", name)
+				}
+			}()
+			ui.NewTester(func(c *ui.Context) { Use(c, Settings{}); IndicatorPane(c, candles, &view, &p, IndicatorPaneOptions{}) }, 300, 200)
+		}()
+	}
+}
+
+func TestIndicatorPaneSnapshot(t *testing.T) {
+	candles := sampleCandles(120)
+	view := MarketView{Count: 80}
+	panes := IndicatorPanes{Panes: []IndicatorPaneSpec{{Kind: IndicatorMACD}, {Kind: IndicatorKDJ}}}
+	snapshot(t, "indicator_pane", 640, 340, func(c *ui.Context) {
+		ui.Column(c).Padding(12).Children(func() {
+			IndicatorPane(c, candles, &view, &panes, IndicatorPaneOptions{Height: 316})
+		})
+	})
+}
diff --git a/messages_mktchart.go b/messages_mktchart.go
index e804b54..97e1603 100644
--- a/messages_mktchart.go
+++ b/messages_mktchart.go
@@ -13,6 +13,7 @@ func init() {
 		"chart_sync.link":          {"Sync with other charts", "与其他图表同步"},
 		"chart_sync.linked":        {"Synced", "已同步"},
 		"chart_sync.unlinked":      {"Not synced", "未同步"},
+		"indicator_pane.remove":    {"Remove %s", "移除 %s"},
 		"drawing_tools.note":       {"Note", "标注"},
 	})
 }
diff --git a/testdata/snapshots/darwin/indicator_pane-dark.png b/testdata/snapshots/darwin/indicator_pane-dark.png
new file mode 100644
index 0000000..5e3cda3
Binary files /dev/null and b/testdata/snapshots/darwin/indicator_pane-dark.png differ
diff --git a/testdata/snapshots/darwin/indicator_pane-light.png b/testdata/snapshots/darwin/indicator_pane-light.png
new file mode 100644
index 0000000..f4df8bd
Binary files /dev/null and b/testdata/snapshots/darwin/indicator_pane-light.png differ
diff --git a/testdata/snapshots/darwin/volume_chart-dark.png b/testdata/snapshots/darwin/volume_chart-dark.png
new file mode 100644
index 0000000..cbaf592
Binary files /dev/null and b/testdata/snapshots/darwin/volume_chart-dark.png differ
diff --git a/testdata/snapshots/darwin/volume_chart-light.png b/testdata/snapshots/darwin/volume_chart-light.png
new file mode 100644
index 0000000..ec4a431
Binary files /dev/null and b/testdata/snapshots/darwin/volume_chart-light.png differ
diff --git a/volume_chart.go b/volume_chart.go
new file mode 100644
index 0000000..6885fb2
--- /dev/null
+++ b/volume_chart.go
@@ -0,0 +1,139 @@
+package mujica
+
+import (
+	"math"
+	"strings"
+
+	"github.com/egoist/mygo/ui"
+
+	"mujicaui/internal"
+	"mujicaui/theme"
+)
+
+// VolumeChartOptions configure a VolumeChart.
+type VolumeChartOptions struct {
+	Frame ChartFrame
+	// Sync links the crosshair to other charts under SyncID.
+	Sync   *ChartSync
+	SyncID string
+}
+
+// VolumeChart draws the volume of the view's window as bars, hollow on rises and filled on falls; give it the price chart's view to share the time axis.
+func VolumeChart(c *ui.Context, candles []Candle, view *MarketView, opts VolumeChartOptions) ChartResult {
+	if view == nil {
+		panic("mujica: VolumeChart needs a view")
+	}
+	if opts.Sync != nil && opts.SyncID == "" {
+		panic("mujica: VolumeChart Sync needs a SyncID")
+	}
+	if opts.Frame.Height == 0 {
+		opts.Frame.Height = 120
+	}
+	ch := newChart(c, opts.Frame)
+	chartMemo(ch, "check", chartID(candles), func() bool { marketCheckCandles(candles); return true })
+	m := &mktCore{c: c, k: Tokens(c), ch: ch, candles: candles, view: view}
+	if s := opts.Sync; s != nil {
+		s.load(opts.SyncID, candles, view)
+	}
+	m.window()
+	hi := chartMemo(ch, "vmax", [3]any{chartID(candles), m.from, m.to}, func() float64 {
+		v := 0.0
+		for i := m.from; i < m.to; i++ {
+			v = max(v, candles[i].Volume)
+		}
+		return v
+	})
+	k := m.k
+	size := FontSize(c, theme.CaptionSize)
+	geom := func(r ui.Rect) (ui.Rect, internal.Band, internal.Linear, []float64, float64) {
+		plot := chartInset(r, 60, 4)
+		lo, top, step := internal.Nice(0, max(hi, 1), 2)
+		return plot, internal.Band{N: m.to - m.from, R0: plot.X, R1: plot.X + plot.W, Pad: 0.3},
+			internal.Linear{D0: lo, D1: top, R0: float64(plot.Y + plot.H), R1: float64(plot.Y)}, internal.Ticks(lo, top, step), step
+	}
+	spec := chartSpec{n: len(candles)}
+	if m.to <= m.from {
+		spec.n = 0
+	}
+	spec.pick = func(r ui.Rect, x, y float32) int {
+		plot, band, _, _, _ := geom(r)
+		if !plot.Contains(x, y) {
+			return -1
+		}
+		return max(m.from, min(m.to-1, m.from+int((x-band.R0)/band.Step())))
+	}
+	spec.readout = func(i int) string {
+		cd := candles[i]
+		return strings.Join([]string{cd.Time.Format("2006-01-02 15:04"), msg(c, "candlestick_chart.volume") + " " + statisticFormat(cd.Volume, 0),
+			trendWord(c, trendSign(cd.Close-cd.Open))}, " · ")
+	}
+	spec.draw = func(p *ui.Painter, r ui.Rect, active int) {
+		plot, band, ys, ticks, step := geom(r)
+		internal.AxisY(p, plot, ys, ticks, func(v float64) string { return volumeShort(v, step) }, size, k)
+		w := max(1, band.Width())
+		at := active
+		if at < 0 && opts.Sync != nil {
+			at = opts.Sync.cursorIndex(opts.SyncID, candles)
+		}
+		for i := m.from; i < m.to; i++ {
+			cd := candles[i]
+			x := internal.Snap(p, band.Center(i-m.from))
+			y := ys.Map(cd.Volume)
+			bar := ui.Rect{X: x - w/2, Y: y, W: w, H: plot.Y + plot.H - y}
+			up := cd.Close >= cd.Open
+			col := trendColor(c, 1)
+			if !up {
+				col = trendColor(c, -1)
+			}
+			if up && w >= 3 {
+				p.Fill(bar, k.Surface, 0)
+				p.Stroke(bar, col, 0, 1)
+			} else {
+				p.Fill(bar, col, 0)
+			}
+		}
+		m.st0().drawn = m.to - m.from
+		if at >= m.from && at < m.to {
+			x := internal.Snap(p, band.Center(at-m.from))
+			p.Line(x, plot.Y, x, plot.Y+plot.H, 1, k.TextMuted)
+		}
+	}
+	res, plot := ch.build(spec)
+	if plot != nil && !plot.IsDisabled() {
+		room := m.room()
+		switch {
+		case plot.Shortcut(ui.Shift, ui.KeyLeft):
+			marketPan(view, len(candles), room, -max(1, (m.to-m.from)/10))
+		case plot.Shortcut(ui.Shift, ui.KeyRight):
+			marketPan(view, len(candles), room, max(1, (m.to-m.from)/10))
+		}
+		if f := ch.st.focus; f >= 0 && (f < m.from || f >= m.to) {
+			ch.st.focus = max(m.from, min(m.to-1, f))
+		}
+	}
+	if s := opts.Sync; s != nil {
+		s.store(opts.SyncID, candles, view, res.Point)
+	}
+	return res
+}
+
+// st0 is the chart's market state, made on first use.
+func (m *mktCore) st0() *mktState {
+	if m.st == nil {
+		m.st = *ui.Local(m.ch.res.Element, "mujica.mkt", func() *mktState { return &mktState{grab: -1, focus: -1} })
+	}
+	return m.st
+}
+
+// volumeShort writes a volume tick as 1.2K, 3M or 4B.
+func volumeShort(v, step float64) string {
+	for _, u := range []struct {
+		div  float64
+		unit string
+	}{{1e9, "B"}, {1e6, "M"}, {1e3, "K"}} {
+		if math.Abs(v) >= u.div {
+			return internal.FormatTick(v/u.div, step/u.div) + u.unit
+		}
+	}
+	return internal.FormatTick(v, step)
+}
diff --git a/volume_chart_test.go b/volume_chart_test.go
new file mode 100644
index 0000000..ef563d6
--- /dev/null
+++ b/volume_chart_test.go
@@ -0,0 +1,56 @@
+package mujica
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/egoist/mygo/ui"
+)
+
+func TestVolumeChartSharesViewAndReads(t *testing.T) {
+	candles := sampleCandles(100000)
+	view := MarketView{Count: 60}
+	var price, vol ChartResult
+	tt := ui.NewTester(func(c *ui.Context) {
+		Use(c, Settings{})
+		ui.Column(c).Width(800).Children(func() {
+			price = CandlestickChart(c, candles, &view, CandlestickOptions{Frame: ChartFrame{Label: "Price"}})
+			vol = VolumeChart(c, candles, &view, VolumeChartOptions{Frame: ChartFrame{Label: "Volume"}})
+		})
+	}, 820, 600)
+	tt.Frame()
+	if d := mktState0(vol).drawn; d != 60 {
+		t.Fatalf("volume drew %d bars", d)
+	}
+	tt.Key(0, ui.KeyTab)
+	tt.Key(0, ui.KeyTab)
+	tt.Key(0, ui.KeyEnd)
+	found := false
+	for _, s := range tt.Texts() {
+		found = found || strings.HasPrefix(s, candles[99999].Time.Format("2006-01-02 15:04")+" · Vol ")
+	}
+	if !found || vol.Point != 99999 {
+		t.Fatalf("readout %q point %d", tt.Texts(), vol.Point)
+	}
+	tt.Key(ui.Shift, ui.KeyLeft)
+	if view.End == 0 {
+		t.Fatal("Shift+Left on volume did not pan the shared view")
+	}
+	_ = price
+	defer func() {
+		if recover() == nil {
+			t.Fatal("nil view accepted")
+		}
+	}()
+	ui.NewTester(func(c *ui.Context) { Use(c, Settings{}); VolumeChart(c, candles, nil, VolumeChartOptions{}) }, 200, 100)
+}
+
+func TestVolumeChartSnapshot(t *testing.T) {
+	candles := sampleCandles(80)
+	view := MarketView{Count: 60}
+	snapshot(t, "volume_chart", 640, 180, func(c *ui.Context) {
+		ui.Column(c).Padding(12).Children(func() {
+			VolumeChart(c, candles, &view, VolumeChartOptions{Frame: ChartFrame{Label: "Volume"}})
+		})
+	})
+}