Fix mouse wheel overlay routing

internal/app/app_input_mouse.go

@@ -97,23 +97,31 @@ func (a *App) routeMouseWheel(msg tea.MouseWheelMsg) tea.Cmd {
 		return nil
 	}
 
+	if (a.dialog != nil && a.dialog.Visible()) ||
+		(a.filePicker != nil && a.filePicker.Visible()) ||
+		(a.settingsDialog != nil && a.settingsDialog.Visible()) ||
+		a.err != nil ||
+		a.toastCoversPoint(msg.X, msg.Y) {
+		// Modal, error, and toast overlays should block background scrolling.
+		return nil
+	}
+
 	targetPane := a.focusedPane
-	// Modal overlays and toast overlays do not consume wheel today, so preserve
-	// focused-pane routing instead of hit-testing obscured panes beneath them.
-	if !a.overlayVisible() && !a.toastCoversPoint(msg.X, msg.Y) {
-		// Route wheel input by pointer target when possible so hovered panes
-		// scroll without requiring a prior click. Fall back to keyboard focus
-		// when the pointer is outside interactive pane geometry.
-		hoverPane, hasTarget := a.paneForPoint(msg.X, msg.Y)
-		if hasTarget {
-			// Dashboard wheel handling activates rows, so do not retarget passive
-			// hover wheel input into it from another pane.
-			if hoverPane != messages.PaneDashboard || a.focusedPane == messages.PaneDashboard {
-				if a.canRetargetWheelToPane(hoverPane) {
-					targetPane = hoverPane
-				}
-			}
+	// Route wheel input by pointer target when possible so hovered panes scroll
+	// without requiring a prior click. If the pointer is over another pane that
+	// cannot handle wheel input, consume the event instead of scrolling the
+	// previously focused pane behind it.
+	hoverPane, hasTarget := a.paneForPoint(msg.X, msg.Y)
+	if hasTarget && hoverPane != a.focusedPane {
+		// Dashboard wheel handling activates rows, so do not retarget passive
+		// hover wheel input into it from another pane.
+		if hoverPane == messages.PaneDashboard {
+			return nil
+		}
+		if !a.canRetargetWheelToPane(hoverPane) {
+			return nil
 		}
+		targetPane = hoverPane
 	}
 
 	var focusCmd tea.Cmd

internal/app/app_input_mouse_helpers_test.go

@@ -0,0 +1,42 @@
+package app
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/andyrewlee/amux/internal/messages"
+	"github.com/andyrewlee/amux/internal/ui/center"
+)
+
+func newScrollableCenterWheelHarness(t *testing.T) (*App, *center.Tab) {
+	t.Helper()
+
+	h, err := NewHarness(HarnessOptions{
+		Mode:    HarnessCenter,
+		Tabs:    1,
+		Width:   140,
+		Height:  40,
+		HotTabs: 0,
+	})
+	if err != nil {
+		t.Fatalf("harness init: %v", err)
+	}
+	if h.app == nil || len(h.tabs) != 1 || h.tabs[0] == nil || h.tabs[0].Terminal == nil {
+		t.Fatal("expected harness center tab terminal")
+	}
+
+	tab := h.tabs[0]
+	for i := 0; i < 80; i++ {
+		tab.WriteToTerminal([]byte(fmt.Sprintf("line %d\n", i)))
+	}
+	tab.Terminal.ScrollView(12)
+	offset, _ := tab.Terminal.GetScrollInfo()
+	if offset == 0 {
+		t.Fatal("expected center terminal to start scrolled into history")
+	}
+
+	if cmd := h.app.focusPane(messages.PaneCenter); cmd != nil {
+		t.Fatal("expected scroll harness focus to be synchronous")
+	}
+	return h.app, tab
+}

internal/app/app_input_mouse_test.go

@@ -181,6 +181,29 @@ func TestRouteMouseWheel_PrefixPaletteConsumesWheel(t *testing.T) {
 	}
 }
 
+func TestRouteMouseWheel_PrefixModeOutsidePaletteStillScrollsFocusedPane(t *testing.T) {
+	app, tab := newScrollableCenterWheelHarness(t)
+	app.prefixActive = true
+
+	l := app.layout
+	x := l.LeftGutter() + l.DashboardWidth() + l.GapX() + 3
+	y := l.TopGutter() + 2
+	if app.prefixPaletteContainsPoint(x, y) {
+		t.Fatal("expected wheel point to be outside prefix palette")
+	}
+
+	before, _ := tab.Terminal.GetScrollInfo()
+	app.routeMouseWheel(tea.MouseWheelMsg{
+		Button: tea.MouseWheelDown,
+		X:      x,
+		Y:      y,
+	})
+	after, _ := tab.Terminal.GetScrollInfo()
+	if after >= before {
+		t.Fatalf("expected prefix mode wheel outside palette to scroll focused center pane, before=%d after=%d", before, after)
+	}
+}
+
 func TestRouteMouseWheel_FocusesHoveredSidebarAndScrollsChanges(t *testing.T) {
 	l := layout.NewManager()
 	l.Resize(140, 40)
@@ -263,6 +286,25 @@ func TestRouteMouseWheel_HoverSidebarTerminalSkipsFocusSideEffects(t *testing.T)
 	}
 }
 
+func TestRouteMouseWheel_HoverSidebarTerminalDoesNotScrollFocusedCenter(t *testing.T) {
+	app, tab := newScrollableCenterWheelHarness(t)
+
+	l := app.layout
+	sidebarStartX := l.LeftGutter() + l.DashboardWidth() + l.GapX() + l.CenterWidth() + l.GapX()
+	topPaneHeight, _ := sidebarPaneHeights(l.Height())
+
+	before, _ := tab.Terminal.GetScrollInfo()
+	app.routeMouseWheel(tea.MouseWheelMsg{
+		Button: tea.MouseWheelDown,
+		X:      sidebarStartX + 3,
+		Y:      l.TopGutter() + topPaneHeight + 2,
+	})
+	after, _ := tab.Terminal.GetScrollInfo()
+	if after != before {
+		t.Fatalf("expected hovered empty sidebar terminal to leave center scroll unchanged, before=%d after=%d", before, after)
+	}
+}
+
 func TestRouteMouseWheel_HoverCenterPreservesDetachedReattach(t *testing.T) {
 	l := layout.NewManager()
 	l.Resize(140, 40)
@@ -310,18 +352,10 @@ func TestRouteMouseWheel_HoverCenterPreservesDetachedReattach(t *testing.T) {
 }
 
 func TestRouteMouseWheel_HoverDashboardDoesNotRetargetFromFocusedPane(t *testing.T) {
-	l := layout.NewManager()
-	l.Resize(140, 40)
+	app, tab := newScrollableCenterWheelHarness(t)
+	l := app.layout
 
-	app := &App{
-		layout:          l,
-		dashboard:       dashboard.New(),
-		center:          center.New(&config.Config{}),
-		sidebar:         sidebar.NewTabbedSidebar(),
-		sidebarTerminal: sidebar.NewTerminalModel(),
-	}
-	app.updateLayout()
-	app.focusPane(messages.PaneCenter)
+	before, _ := tab.Terminal.GetScrollInfo()
 
 	cmd := app.routeMouseWheel(tea.MouseWheelMsg{
 		Button: tea.MouseWheelDown,
@@ -334,6 +368,10 @@ func TestRouteMouseWheel_HoverDashboardDoesNotRetargetFromFocusedPane(t *testing
 	if app.focusedPane != messages.PaneCenter {
 		t.Fatalf("expected focus to remain center, got %v", app.focusedPane)
 	}
+	after, _ := tab.Terminal.GetScrollInfo()
+	if after != before {
+		t.Fatalf("expected dashboard hover wheel to leave center scroll unchanged, before=%d after=%d", before, after)
+	}
 }
 
 func TestRouteMouseWheel_HoverEmptyCenterDoesNotStealFocus(t *testing.T) {
@@ -362,66 +400,30 @@ func TestRouteMouseWheel_HoverEmptyCenterDoesNotStealFocus(t *testing.T) {
 }
 
 func TestRouteMouseWheel_DialogOverlayPreventsRetarget(t *testing.T) {
-	l := layout.NewManager()
-	l.Resize(140, 40)
-
-	app := &App{
-		layout:          l,
-		dashboard:       dashboard.New(),
-		center:          center.New(&config.Config{}),
-		sidebar:         sidebar.NewTabbedSidebar(),
-		sidebarTerminal: sidebar.NewTerminalModel(),
-		dialog:          common.NewConfirmDialog("quit", "Quit", "Confirm?"),
-	}
+	app, tab := newScrollableCenterWheelHarness(t)
+	l := app.layout
+	app.dialog = common.NewConfirmDialog("quit", "Quit", "Confirm?")
 	app.dialog.Show()
-	app.updateLayout()
-	app.focusPane(messages.PaneDashboard)
 
 	centerStartX := l.LeftGutter() + l.DashboardWidth() + l.GapX()
+	before, _ := tab.Terminal.GetScrollInfo()
 	_ = app.routeMouseWheel(tea.MouseWheelMsg{
 		Button: tea.MouseWheelDown,
 		X:      centerStartX + 3,
 		Y:      l.TopGutter() + 2,
 	})
-	if app.focusedPane != messages.PaneDashboard {
-		t.Fatalf("expected dialog overlay to preserve dashboard focus, got %v", app.focusedPane)
+	if app.focusedPane != messages.PaneCenter {
+		t.Fatalf("expected dialog overlay to preserve center focus, got %v", app.focusedPane)
+	}
+	after, _ := tab.Terminal.GetScrollInfo()
+	if after != before {
+		t.Fatalf("expected dialog overlay to block background scrolling, before=%d after=%d", before, after)
 	}
 }
 
 func TestRouteMouseWheel_ToastOverlayPreventsRetarget(t *testing.T) {
-	l := layout.NewManager()
-	l.Resize(140, 40)
-
-	cfg := &config.Config{
-		Assistants: map[string]config.AssistantConfig{
-			"codex": {Command: "codex"},
-		},
-	}
-	centerModel := center.New(cfg)
-	app := &App{
-		width:           140,
-		height:          40,
-		layout:          l,
-		dashboard:       dashboard.New(),
-		center:          centerModel,
-		sidebar:         sidebar.NewTabbedSidebar(),
-		sidebarTerminal: sidebar.NewTerminalModel(),
-		toast:           common.NewToastModel(),
-	}
-	app.updateLayout()
-
-	ws := data.NewWorkspace("feature", "feature", "main", "/tmp/repo", "/tmp/repo/feature")
-	ws.OpenTabs = []data.TabInfo{{
-		Assistant:   "codex",
-		Name:        "Codex",
-		SessionName: "amux-test-toast-detached",
-		Status:      "detached",
-	}}
-	centerModel.SetWorkspace(ws)
-	if cmd := centerModel.RestoreTabsFromWorkspace(ws); cmd != nil {
-		t.Fatal("expected detached tab restore to be synchronous")
-	}
-	app.focusPane(messages.PaneDashboard)
+	app, tab := newScrollableCenterWheelHarness(t)
+	l := app.layout
 
 	_ = app.toast.ShowInfo(strings.Repeat("toast ", 12))
 	toastView := app.toast.View()
@@ -452,6 +454,7 @@ func TestRouteMouseWheel_ToastOverlayPreventsRetarget(t *testing.T) {
 		t.Fatal("expected toast height to be positive")
 	}
 
+	before, _ := tab.Terminal.GetScrollInfo()
 	cmd := app.routeMouseWheel(tea.MouseWheelMsg{
 		Button: tea.MouseWheelDown,
 		X:      x,
@@ -460,7 +463,11 @@ func TestRouteMouseWheel_ToastOverlayPreventsRetarget(t *testing.T) {
 	if cmd != nil {
 		t.Fatal("expected toast-covered wheel input to avoid retarget side effects")
 	}
-	if app.focusedPane != messages.PaneDashboard {
-		t.Fatalf("expected toast overlay to preserve dashboard focus, got %v", app.focusedPane)
+	if app.focusedPane != messages.PaneCenter {
+		t.Fatalf("expected toast overlay to preserve center focus, got %v", app.focusedPane)
+	}
+	after, _ := tab.Terminal.GetScrollInfo()
+	if after != before {
+		t.Fatalf("expected toast overlay to block background scrolling, before=%d after=%d", before, after)
 	}
 }