diff --git a/server/procBuilder.go b/server/procBuilder.go
index 5eaadeefa..575c1ca9f 100644
--- a/server/procBuilder.go
+++ b/server/procBuilder.go
@@ -59,7 +59,9 @@ func (b *procBuilder) Build() ([]*buildItem, error) {
 
 	sort.Sort(remote.ByName(b.Yamls))
 
-	for j, y := range b.Yamls {
+	pidSequence := 1
+
+	for _, y := range b.Yamls {
 		// matrix axes
 		axes, err := matrix.ParseString(string(y.Data))
 		if err != nil {
@@ -69,11 +71,11 @@ func (b *procBuilder) Build() ([]*buildItem, error) {
 			axes = append(axes, matrix.Axis{})
 		}
 
-		for i, axis := range axes {
+		for _, axis := range axes {
 			proc := &model.Proc{
 				BuildID: b.Curr.ID,
-				PID:     j + i + 1,
-				PGID:    j + i + 1,
+				PID:     pidSequence,
+				PGID:    pidSequence,
 				State:   model.StatusPending,
 				Environ: axis,
 				Name:    sanitizePath(y.Name),
@@ -123,6 +125,7 @@ func (b *procBuilder) Build() ([]*buildItem, error) {
 				item.Labels = map[string]string{}
 			}
 			items = append(items, item)
+			pidSequence++
 		}
 	}
 
diff --git a/server/procBuilder_test.go b/server/procBuilder_test.go
index 4452dfaf4..d5f32ae7f 100644
--- a/server/procBuilder_test.go
+++ b/server/procBuilder_test.go
@@ -201,6 +201,42 @@ pipeline:
 		}
 	}
 	if buildItems[1].Proc.State != model.StatusPending {
-		t.Fatal("Should not run on dev branch")
+		t.Fatal("Should run on dev branch")
+	}
+}
+
+func TestTree(t *testing.T) {
+	build := &model.Build{}
+
+	b := procBuilder{
+		Repo:  &model.Repo{},
+		Curr:  build,
+		Last:  &model.Build{},
+		Netrc: &model.Netrc{},
+		Secs:  []*model.Secret{},
+		Regs:  []*model.Registry{},
+		Link:  "",
+		Yamls: []*remote.FileMeta{
+			&remote.FileMeta{Data: []byte(`
+pipeline:
+  build:
+    image: scratch
+    yyy: ${DRONE_COMMIT_MESSAGE}
+`)},
+		},
+	}
+
+	_, err := b.Build()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(build.Procs) != 3 {
+		t.Fatal("Should generate three in total")
+	}
+	if build.Procs[1].PPID != 1 {
+		t.Fatal("Clone step should be a children of the stage")
+	}
+	if build.Procs[2].PPID != 1 {
+		t.Fatal("Build step should be a children of the stage")
 	}
 }