diff --git a/OpenRA.Mods.Common/Activities/DeliverResources.cs b/OpenRA.Mods.Common/Activities/DeliverResources.cs
index 79085c5d5b..166473bdd3 100644
--- a/OpenRA.Mods.Common/Activities/DeliverResources.cs
+++ b/OpenRA.Mods.Common/Activities/DeliverResources.cs
@@ -30,12 +30,17 @@ namespace OpenRA.Mods.Common.Activities
 		{
 			movement = self.Trait<IMove>();
 			harv = self.Trait<Harvester>();
-			IsInterruptible = false;
 		}
 
 		public override Activity Tick(Actor self)
 		{
-			if (NextActivity != null)
+			if (ChildActivity != null)
+			{
+				ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
+				return this;
+			}
+
+			if (IsCanceling || isDocking)
 				return NextActivity;
 
 			// Find the nearest best refinery if not explicitly ordered to a specific refinery:
@@ -57,7 +62,10 @@ namespace OpenRA.Mods.Common.Activities
 
 			// No refineries exist; check again after delay defined in Harvester.
 			if (harv.LinkedProc == null)
-				return ActivityUtils.SequenceActivities(self, new Wait(harv.Info.SearchForDeliveryBuildingDelay), this);
+			{
+				QueueChild(self, new Wait(harv.Info.SearchForDeliveryBuildingDelay), true);
+				return this;
+			}
 
 			var proc = harv.LinkedProc;
 			var iao = proc.Trait<IAcceptResources>();
@@ -68,16 +76,19 @@ namespace OpenRA.Mods.Common.Activities
 				foreach (var n in self.TraitsImplementing<INotifyHarvesterAction>())
 					n.MovingToRefinery(self, proc, null);
 
-				return ActivityUtils.SequenceActivities(self, movement.MoveTo(proc.Location + iao.DeliveryOffset, 0), this);
+				QueueChild(self, movement.MoveTo(proc.Location + iao.DeliveryOffset, 0), true);
+				return this;
 			}
 
 			if (!isDocking)
 			{
+				QueueChild(self, new Wait(10), true);
 				isDocking = true;
 				iao.OnDock(self, this);
+				return this;
 			}
 
-			return ActivityUtils.SequenceActivities(self, new Wait(10), this);
+			return NextActivity;
 		}
 	}
 }
diff --git a/OpenRA.Mods.Common/Activities/HarvesterDockSequence.cs b/OpenRA.Mods.Common/Activities/HarvesterDockSequence.cs
index 78fdee3466..92f60ad1fe 100644
--- a/OpenRA.Mods.Common/Activities/HarvesterDockSequence.cs
+++ b/OpenRA.Mods.Common/Activities/HarvesterDockSequence.cs
@@ -19,7 +19,7 @@ namespace OpenRA.Mods.Common.Activities
 {
 	public abstract class HarvesterDockSequence : Activity
 	{
-		protected enum DockingState { Wait, Turn, Dock, Loop, Undock, Complete }
+		protected enum DockingState { Wait, Turn, Dock, Loop, Undock, Complete, Finished }
 
 		protected readonly Actor Refinery;
 		protected readonly Harvester Harv;
@@ -47,34 +47,54 @@ namespace OpenRA.Mods.Common.Activities
 
 		public override Activity Tick(Actor self)
 		{
+			if (ChildActivity != null)
+			{
+				ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
+				return this;
+			}
+
 			switch (dockingState)
 			{
 				case DockingState.Wait:
 					return this;
+
 				case DockingState.Turn:
 					dockingState = DockingState.Dock;
+					QueueChild(self, new Turn(self, DockAngle), true);
 					if (IsDragRequired)
-						return ActivityUtils.SequenceActivities(self, new Turn(self, DockAngle), new Drag(self, StartDrag, EndDrag, DragLength), this);
-					return ActivityUtils.SequenceActivities(self, new Turn(self, DockAngle), this);
+						QueueChild(self, new Drag(self, StartDrag, EndDrag, DragLength));
+					return this;
+
 				case DockingState.Dock:
 					if (Refinery.IsInWorld && !Refinery.IsDead)
 						foreach (var nd in Refinery.TraitsImplementing<INotifyDocking>())
 							nd.Docked(Refinery, self);
+
 					return OnStateDock(self);
+
 				case DockingState.Loop:
 					if (!Refinery.IsInWorld || Refinery.IsDead || Harv.TickUnload(self, Refinery))
 						dockingState = DockingState.Undock;
+
 					return this;
+
 				case DockingState.Undock:
 					return OnStateUndock(self);
+
 				case DockingState.Complete:
 					if (Refinery.IsInWorld && !Refinery.IsDead)
 						foreach (var nd in Refinery.TraitsImplementing<INotifyDocking>())
 							nd.Undocked(Refinery, self);
+
 					Harv.LastLinkedProc = Harv.LinkedProc;
 					Harv.LinkProc(self, null);
 					if (IsDragRequired)
-						return ActivityUtils.SequenceActivities(self, new Drag(self, EndDrag, StartDrag, DragLength), NextActivity);
+						QueueChild(self, new Drag(self, EndDrag, StartDrag, DragLength), true);
+
+					dockingState = DockingState.Finished;
+					return this;
+
+				case DockingState.Finished:
 					return NextActivity;
 			}
 
diff --git a/OpenRA.Mods.Common/Traits/Buildings/Refinery.cs b/OpenRA.Mods.Common/Traits/Buildings/Refinery.cs
index c20bd59934..3ca4054a40 100644
--- a/OpenRA.Mods.Common/Traits/Buildings/Refinery.cs
+++ b/OpenRA.Mods.Common/Traits/Buildings/Refinery.cs
@@ -144,12 +144,12 @@ namespace OpenRA.Mods.Common.Traits
 		{
 			if (!preventDock)
 			{
-				dockOrder.Queue(self, new CallFunc(() => dockedHarv = harv, false));
-				dockOrder.Queue(self, DockSequence(harv, self));
-				dockOrder.Queue(self, new CallFunc(() => dockedHarv = null, false));
+				dockOrder.QueueChild(self, new CallFunc(() => dockedHarv = harv, false));
+				dockOrder.QueueChild(self, DockSequence(harv, self));
+				dockOrder.QueueChild(self, new CallFunc(() => dockedHarv = null, false));
 			}
 
-			dockOrder.Queue(self, new CallFunc(() => harv.Trait<Harvester>().ContinueHarvesting(harv)));
+			dockOrder.QueueChild(self, new CallFunc(() => harv.Trait<Harvester>().ContinueHarvesting(harv)));
 		}
 
 		void INotifyOwnerChanged.OnOwnerChanged(Actor self, Player oldOwner, Player newOwner)
diff --git a/OpenRA.Mods.Common/Traits/Harvester.cs b/OpenRA.Mods.Common/Traits/Harvester.cs
index 6f5f0d1d3e..b6db5283a1 100644
--- a/OpenRA.Mods.Common/Traits/Harvester.cs
+++ b/OpenRA.Mods.Common/Traits/Harvester.cs
@@ -397,7 +397,8 @@ namespace OpenRA.Mods.Common.Traits
 				LinkProc(self, OwnerLinkedProc = null);
 				idleSmart = true;
 
-				self.CancelActivity();
+				if (!order.Queued)
+					self.CancelActivity();
 
 				CPos loc;
 				if (order.Target.Type != TargetType.Invalid)
@@ -442,7 +443,9 @@ namespace OpenRA.Mods.Common.Traits
 
 				self.SetTargetLine(order.Target, Color.Green);
 
-				self.CancelActivity();
+				if (!order.Queued)
+					self.CancelActivity();
+
 				self.QueueActivity(new DeliverResources(self));
 
 				foreach (var n in notifyHarvesterAction)