diff --git a/pkg/gocui/gui.go b/pkg/gocui/gui.go
index 103c90483..bb9fc9874 100644
--- a/pkg/gocui/gui.go
+++ b/pkg/gocui/gui.go
@@ -603,6 +603,13 @@ func (g *Gui) SetRenderSearchStatusFunc(renderSearchStatusFunc func(*View, int,
 	g.renderSearchStatusFunc = renderSearchStatusFunc
 }
 
+// SetUpdateQueueHighWaterMarkHandler registers a diagnostic callback invoked
+// with the new depth whenever the queue of pending Update callbacks reaches a
+// new maximum. It may be called from any goroutine.
+func (g *Gui) SetUpdateQueueHighWaterMarkHandler(f func(depth int)) {
+	g.userEvents.setHighWaterMarkHandler(f)
+}
+
 // userEvent represents an event triggered by the user.
 type userEvent struct {
 	f    func(*Gui) error
@@ -639,6 +646,13 @@ type userEventQueue struct {
 	mutex    sync.Mutex
 	events   []userEvent
 	doorbell chan struct{}
+
+	// highWaterMark is the deepest the queue has ever been, and
+	// onHighWaterMark (if set) is called with the new depth each time that
+	// record is broken. Purely diagnostic: it lets us see how deep the queue
+	// gets in practice (see SetUpdateQueueHighWaterMarkHandler).
+	highWaterMark   int
+	onHighWaterMark func(int)
 }
 
 func newUserEventQueue() *userEventQueue {
@@ -649,14 +663,32 @@ func newUserEventQueue() *userEventQueue {
 func (q *userEventQueue) enqueue(ev userEvent) {
 	q.mutex.Lock()
 	q.events = append(q.events, ev)
+	newHighWaterMark := 0
+	if len(q.events) > q.highWaterMark {
+		q.highWaterMark = len(q.events)
+		newHighWaterMark = q.highWaterMark
+	}
+	onHighWaterMark := q.onHighWaterMark
 	q.mutex.Unlock()
 
+	// Report outside the lock: the handler does I/O (logging) and must not
+	// stall other producers or the draining loop.
+	if newHighWaterMark > 0 && onHighWaterMark != nil {
+		onHighWaterMark(newHighWaterMark)
+	}
+
 	select {
 	case q.doorbell <- struct{}{}:
 	default:
 	}
 }
 
+func (q *userEventQueue) setHighWaterMarkHandler(f func(int)) {
+	q.mutex.Lock()
+	q.onHighWaterMark = f
+	q.mutex.Unlock()
+}
+
 // dequeue pops the oldest event, reporting false when the queue is empty.
 func (q *userEventQueue) dequeue() (userEvent, bool) {
 	q.mutex.Lock()
diff --git a/pkg/gocui/user_event_queue_test.go b/pkg/gocui/user_event_queue_test.go
index 10e86eef8..e547debb4 100644
--- a/pkg/gocui/user_event_queue_test.go
+++ b/pkg/gocui/user_event_queue_test.go
@@ -36,6 +36,37 @@ func TestUpdateIsUnboundedAndPreservesOrder(t *testing.T) {
 	assert.Equal(t, want, got)
 }
 
+// The high-water-mark handler fires only when the queue reaches a new maximum
+// depth, reporting that depth. It does not reset when the queue drains.
+func TestUpdateQueueHighWaterMark(t *testing.T) {
+	g := newTestGui(t)
+
+	var marks []int
+	g.SetUpdateQueueHighWaterMarkHandler(func(depth int) { marks = append(marks, depth) })
+
+	noop := func(*Gui) error { return nil }
+
+	// Three enqueues with no drain: new highs 1, 2, 3.
+	g.Update(noop)
+	g.Update(noop)
+	g.Update(noop)
+	_, err := g.processRemainingEvents()
+	assert.NoError(t, err)
+
+	// Two enqueues stay below the previous high of 3: no new marks.
+	g.Update(noop)
+	g.Update(noop)
+	_, err = g.processRemainingEvents()
+	assert.NoError(t, err)
+
+	// Four enqueues with no drain: only depth 4 beats the previous high.
+	for range 4 {
+		g.Update(noop)
+	}
+
+	assert.Equal(t, []int{1, 2, 3, 4}, marks)
+}
+
 // Concurrent producers must be able to enqueue safely (run under -race). Only
 // same-goroutine order is guaranteed, so we check that every event is delivered
 // exactly once and that each producer's own events stay in order.
diff --git a/pkg/gui/gui.go b/pkg/gui/gui.go
index e23afd124..61d4a90e2 100644
--- a/pkg/gui/gui.go
+++ b/pkg/gui/gui.go
@@ -414,6 +414,10 @@ func (gui *Gui) onNewRepo(startArgs appTypes.StartArgs, contextKey types.Context
 		return nil
 	})
 
+	gui.g.SetUpdateQueueHighWaterMarkHandler(func(depth int) {
+		gui.c.Log.Infof("User-event queue reached a new high-water mark: %d", depth)
+	})
+
 	gui.g.SetOnSelectSearchResultFunc(func(v *gocui.View, selectedLineIdx int) {
 		ctx, ok := gui.helpers.View.ContextForView(v.Name())
 		if ok {