diff --git a/src/cmd/trace/annotations.go b/src/cmd/trace/annotations.go
index c7c0b637c7..aa72a50e72 100644
--- a/src/cmd/trace/annotations.go
+++ b/src/cmd/trace/annotations.go
@@ -446,12 +446,42 @@ func (task *taskDesc) overlappingGCDuration(evs []*trace.Event) (overlapping tim
 	return overlapping
 }
 
+// overlappingInstant returns true if the instantaneous event, ev, occurred during
+// any of the task's span if ev is a goroutine-local event, or overlaps with the
+// task's lifetime if ev is a global event.
+func (task *taskDesc) overlappingInstant(ev *trace.Event) bool {
+	if isUserAnnotationEvent(ev) && task.id != ev.Args[0] {
+		return false // not this task's user event.
+	}
+
+	ts := ev.Ts
+	taskStart := task.firstTimestamp()
+	taskEnd := task.lastTimestamp()
+	if ts < taskStart || taskEnd < ts {
+		return false
+	}
+	if ev.P == trace.GCP {
+		return true
+	}
+
+	// Goroutine local event. Check whether there are spans overlapping with the event.
+	goid := ev.G
+	for _, span := range task.spans {
+		if span.goid != goid {
+			continue
+		}
+		if span.firstTimestamp() <= ts && ts <= span.lastTimestamp() {
+			return true
+		}
+	}
+	return false
+}
+
 // overlappingDuration returns whether the durational event, ev, overlaps with
 // any of the task's span if ev is a goroutine-local event, or overlaps with
 // the task's lifetime if ev is a global event. It returns the overlapping time
 // as well.
 func (task *taskDesc) overlappingDuration(ev *trace.Event) (time.Duration, bool) {
-	// TODO: check whether ev is a 'durational' event.
 	start := ev.Ts
 	end := lastTimestamp()
 	if ev.Link != nil {
@@ -463,9 +493,13 @@ func (task *taskDesc) overlappingDuration(ev *trace.Event) (time.Duration, bool)
 	}
 
 	goid := ev.G
+	goid2 := ev.G
+	if ev.Link != nil {
+		goid2 = ev.Link.G
+	}
 
-	// This event is a global event (G=0)
-	if goid == 0 {
+	// This event is a global GC event
+	if ev.P == trace.GCP {
 		taskStart := task.firstTimestamp()
 		taskEnd := task.lastTimestamp()
 		o := overlappingDuration(taskStart, taskEnd, start, end)
@@ -476,7 +510,7 @@ func (task *taskDesc) overlappingDuration(ev *trace.Event) (time.Duration, bool)
 	var overlapping time.Duration
 	var lastSpanEnd int64 // the end of previous overlapping span
 	for _, span := range task.spans {
-		if span.goid != goid {
+		if span.goid != goid && span.goid != goid2 {
 			continue
 		}
 		spanStart, spanEnd := span.firstTimestamp(), span.lastTimestamp()
@@ -925,3 +959,11 @@ func describeEvent(ev *trace.Event) string {
 	}
 	return ""
 }
+
+func isUserAnnotationEvent(ev *trace.Event) bool {
+	switch ev.Type {
+	case trace.EvUserLog, trace.EvUserSpan, trace.EvUserTaskCreate, trace.EvUserTaskEnd:
+		return true
+	}
+	return false
+}
diff --git a/src/cmd/trace/trace.go b/src/cmd/trace/trace.go
index 7dd8a87d94..3a730a313b 100644
--- a/src/cmd/trace/trace.go
+++ b/src/cmd/trace/trace.go
@@ -916,6 +916,23 @@ func (ctx *traceContext) emitThreadCounters(ev *trace.Event) {
 }
 
 func (ctx *traceContext) emitInstant(ev *trace.Event, name, category string) {
+	cname := ""
+	if ctx.mode == taskTraceview && ev.G != 0 {
+		overlapping := false
+		for _, task := range ctx.tasks {
+			if task.overlappingInstant(ev) {
+				overlapping = true
+				break
+			}
+		}
+		// grey out or skip if non-overlapping instant.
+		if !overlapping {
+			if isUserAnnotationEvent(ev) {
+				return // don't display unrelated task events.
+			}
+			cname = "grey"
+		}
+	}
 	var arg interface{}
 	if ev.Type == trace.EvProcStart {
 		type Arg struct {
@@ -931,6 +948,7 @@ func (ctx *traceContext) emitInstant(ev *trace.Event, name, category string) {
 		Time:     ctx.time(ev),
 		Tid:      ctx.proc(ev),
 		Stack:    ctx.stack(ev.Stk),
+		Cname:    cname,
 		Arg:      arg})
 }
 
@@ -950,6 +968,20 @@ func (ctx *traceContext) emitArrow(ev *trace.Event, name string) {
 		ctx.emitInstant(&trace.Event{P: ev.P, Ts: ev.Ts}, "unblock", "")
 	}
 
+	if ctx.mode == taskTraceview {
+		overlapping := false
+		// skip non-overlapping arrows.
+		for _, task := range ctx.tasks {
+			if _, overlapped := task.overlappingDuration(ev); overlapped {
+				overlapping = true
+				break
+			}
+		}
+		if !overlapping {
+			return
+		}
+	}
+
 	ctx.arrowSeq++
 	ctx.emit(&ViewerEvent{Name: name, Phase: "s", Tid: ctx.proc(ev), ID: ctx.arrowSeq, Time: ctx.time(ev), Stack: ctx.stack(ev.Stk)})
 	ctx.emit(&ViewerEvent{Name: name, Phase: "t", Tid: ctx.proc(ev.Link), ID: ctx.arrowSeq, Time: ctx.time(ev.Link)})