Index: ps/trunk/binaries/data/mods/public/gui/session/unit_actions.js
===================================================================
--- ps/trunk/binaries/data/mods/public/gui/session/unit_actions.js
+++ ps/trunk/binaries/data/mods/public/gui/session/unit_actions.js
@@ -1105,6 +1105,33 @@
 		"specificness": 11,
 	},
 
+	// This is a "fake" action to show a failure cursor
+	// when only uncontrollable entities are selected.
+	"uncontrollable":
+	{
+		"execute": function(target, action, selection, queued)
+		{
+			return true;
+		},
+		"actionCheck": function(target, selection)
+		{
+			// Only show this action if all entities are marked uncontrollable.
+			let playerState = g_SimState.players[g_ViewedPlayer];
+			if (playerState && playerState.controlsAll || selection.some(ent => {
+				let entState = GetEntityState(ent);
+				return entState && entState.identity && entState.identity.controllable;
+			}))
+				return false;
+
+			return {
+				"type": "none",
+				"cursor": "cursor-no",
+				"tooltip": translatePlural("This entity cannot be controlled.", "These entities cannot be controlled.", selection.length)
+			};
+		},
+		"specificness": 100,
+	},
+
 	"none":
 	{
 		"execute": function(target, action, selection, queued)
@@ -1600,14 +1627,19 @@
 
 function getActionInfo(action, target, selection)
 {
-	let simState = GetSimState();
-
-	// If the selection doesn't exist, no action
-	if (!GetEntityState(selection[0]))
+	if (!selection || !selection.length || !GetEntityState(selection[0]))
 		return { "possible": false };
 
 	if (!target) // TODO move these non-target actions to an object like unit_actions.js
 	{
+		// Ensure one entity at least is controllable.
+		let playerState = g_SimState.players[g_ViewedPlayer];
+		if (playerState && !playerState.controlsAll && !selection.some(ent => {
+			let entState = GetEntityState(ent);
+			return entState && entState.identity && entState.identity.controllable;
+		}))
+			return { "possible": false };
+
 		if (action == "set-rallypoint")
 		{
 			let cursor = "";
@@ -1644,6 +1676,9 @@
 	if (!targetState)
 		return { "possible": false };
 
+	let simState = GetSimState();
+	let playerState = g_SimState.players[g_ViewedPlayer];
+
 	// Check if any entities in the selection can do some of the available actions with target
 	for (let entityID of selection)
 	{
@@ -1651,6 +1686,9 @@
 		if (!entState)
 			continue;
 
+		if (playerState && !playerState.controlsAll && !entState.identity.controllable)
+			continue;
+
 		if (g_UnitActions[action] && g_UnitActions[action].getActionInfo)
 		{
 			let r = g_UnitActions[action].getActionInfo(entState, targetState, simState);
Index: ps/trunk/binaries/data/mods/public/gui/session/unit_commands.js
===================================================================
--- ps/trunk/binaries/data/mods/public/gui/session/unit_commands.js
+++ ps/trunk/binaries/data/mods/public/gui/session/unit_commands.js
@@ -135,7 +135,13 @@
 	let playerStates = GetSimState().players;
 	let playerState = playerStates[Engine.GetPlayerID()];
 
-	if (g_IsObserver || entStates.every(entState => controlsPlayer(entState.player)))
+	// Always show selection.
+	setupUnitPanel("Selection", entStates, playerStates[entStates[0].player]);
+
+	if (g_IsObserver || entStates.every(entState =>
+		controlsPlayer(entState.player) &&
+		(!entState.identity || entState.identity.controllable)) ||
+		playerState.controlsAll)
 	{
 		for (let guiName of g_PanelsOrder)
 		{
Index: ps/trunk/binaries/data/mods/public/simulation/components/GuiInterface.js
===================================================================
--- ps/trunk/binaries/data/mods/public/simulation/components/GuiInterface.js
+++ ps/trunk/binaries/data/mods/public/simulation/components/GuiInterface.js
@@ -261,7 +261,8 @@
 			"selectionGroupName": cmpIdentity.GetSelectionGroupName(),
 			"canDelete": !cmpIdentity.IsUndeletable(),
 			"hasSomeFormation": cmpIdentity.HasSomeFormation(),
-			"formations": cmpIdentity.GetFormationsList()
+			"formations": cmpIdentity.GetFormationsList(),
+			"controllable": cmpIdentity.IsControllable()
 		};
 
 	let cmpPosition = Engine.QueryInterface(ent, IID_Position);
Index: ps/trunk/binaries/data/mods/public/simulation/components/Identity.js
===================================================================
--- ps/trunk/binaries/data/mods/public/simulation/components/Identity.js
+++ ps/trunk/binaries/data/mods/public/simulation/components/Identity.js
@@ -90,6 +90,11 @@
 			"<text/>" +
 		"</element>" +
 	"</optional>" +
+	"<optional>" +
+		"<element name='Controllable' a:help='Whether players can control this entity. Defaults to true.'>" +
+			"<data type='boolean'/>" +
+		"</element>" +
+	"</optional>" +
 	"<element name='Undeletable' a:help='Prevent players from deleting this entity.'>" +
 		"<data type='boolean'/>" +
 	"</element>";
@@ -102,6 +107,8 @@
 		this.phenotype = pickRandom(this.GetPossiblePhenotypes());
 	else
 		this.phenotype = "default";
+
+	this.controllable = this.template.Controllable ? this.template.Controllable == "true" : true;
 };
 
 Identity.prototype.HasSomeFormation = function()
@@ -184,4 +191,14 @@
 	return this.template.Undeletable == "true";
 };
 
+Identity.prototype.IsControllable = function()
+{
+	return this.controllable;
+};
+
+Identity.prototype.SetControllable = function(controllability)
+{
+	this.controllable = controllability;
+};
+
 Engine.RegisterComponentType(IID_Identity, "Identity", Identity);
Index: ps/trunk/binaries/data/mods/public/simulation/components/UnitAI.js
===================================================================
--- ps/trunk/binaries/data/mods/public/simulation/components/UnitAI.js
+++ ps/trunk/binaries/data/mods/public/simulation/components/UnitAI.js
@@ -214,8 +214,7 @@
 
 	// Called when being told to walk as part of a formation
 	"Order.FormationWalk": function(msg) {
-		// Let players move captured domestic animals around
-		if (this.IsAnimal() && !this.IsDomestic() || !this.AbleToMove())
+		if (!this.AbleToMove())
 		{
 			this.FinishOrder();
 			return;
@@ -247,13 +246,6 @@
 	// (these will switch the unit out of formation mode)
 
 	"Order.Stop": function(msg) {
-		// We have no control over non-domestic animals.
-		if (this.IsAnimal() && !this.IsDomestic())
-		{
-			this.FinishOrder();
-			return;
-		}
-
 		this.StopMoving();
 		this.FinishOrder();
 
@@ -267,8 +259,7 @@
 	},
 
 	"Order.Walk": function(msg) {
-		// Let players move captured domestic animals around
-		if (this.IsAnimal() && !this.IsDomestic() || !this.AbleToMove())
+		if (!this.AbleToMove())
 		{
 			this.FinishOrder();
 			return;
@@ -289,8 +280,7 @@
 	},
 
 	"Order.WalkAndFight": function(msg) {
-		// Let players move captured domestic animals around
-		if (this.IsAnimal() && !this.IsDomestic() || !this.AbleToMove())
+		if (!this.AbleToMove())
 		{
 			this.FinishOrder();
 			return;
@@ -312,8 +302,7 @@
 
 
 	"Order.WalkToTarget": function(msg) {
-		// Let players move captured domestic animals around
-		if (this.IsAnimal() && !this.IsDomestic() || !this.AbleToMove())
+		if (!this.AbleToMove())
 		{
 			this.FinishOrder();
 			return;
@@ -3341,12 +3330,6 @@
 			this.template.NaturalBehaviour == "aggressive"));
 };
 
-UnitAI.prototype.IsDomestic = function()
-{
-	var cmpIdentity = Engine.QueryInterface(this.entity, IID_Identity);
-	return cmpIdentity && cmpIdentity.HasClass("Domestic");
-};
-
 UnitAI.prototype.IsHealer = function()
 {
 	return Engine.QueryInterface(this.entity, IID_Heal);
Index: ps/trunk/binaries/data/mods/public/simulation/components/tests/test_GuiInterface.js
===================================================================
--- ps/trunk/binaries/data/mods/public/simulation/components/tests/test_GuiInterface.js
+++ ps/trunk/binaries/data/mods/public/simulation/components/tests/test_GuiInterface.js
@@ -548,6 +548,7 @@
 	"GetSelectionGroupName": function() { return "Selection Group Name"; },
 	"HasClass": function() { return true; },
 	"IsUndeletable": function() { return false; },
+	"IsControllable": function() { return true; },
 	"HasSomeFormation": function() { return false; },
 	"GetFormationsList": function() { return []; },
 });
@@ -581,6 +582,7 @@
 		"canDelete": true,
 		"hasSomeFormation": false,
 		"formations": [],
+		"controllable": true,
 	},
 	"position": { "x": 1, "y": 2, "z": 3 },
 	"hitpoints": 50,
Index: ps/trunk/binaries/data/mods/public/simulation/helpers/Commands.js
===================================================================
--- ps/trunk/binaries/data/mods/public/simulation/helpers/Commands.js
+++ ps/trunk/binaries/data/mods/public/simulation/helpers/Commands.js
@@ -340,13 +340,6 @@
 
 	"research": function(player, cmd, data)
 	{
-		if (!CanControlUnit(cmd.entity, player, data.controlAllUnits))
-		{
-			if (g_DebugCommands)
-				warn("Invalid command: research building cannot be controlled by player "+player+": "+uneval(cmd));
-			return;
-		}
-
 		var cmpTechnologyManager = QueryOwnerInterface(cmd.entity, IID_TechnologyManager);
 		if (cmpTechnologyManager && !cmpTechnologyManager.CanResearch(cmd.template))
 		{
@@ -362,13 +355,6 @@
 
 	"stop-production": function(player, cmd, data)
 	{
-		if (!CanControlUnit(cmd.entity, player, data.controlAllUnits))
-		{
-			if (g_DebugCommands)
-				warn("Invalid command: production building cannot be controlled by player "+player+": "+uneval(cmd));
-			return;
-		}
-
 		var queue = Engine.QueryInterface(cmd.entity, IID_ProductionQueue);
 		if (queue)
 			queue.RemoveBatch(cmd.id);
@@ -458,8 +444,7 @@
 
 	"garrison": function(player, cmd, data)
 	{
-		// Verify that the building can be controlled by the player or is mutualAlly
-		if (!CanControlUnitOrIsAlly(cmd.target, player, data.controlAllUnits))
+		if (!CanPlayerOrAllyControlUnit(cmd.target, player, data.controlAllUnits))
 		{
 			if (g_DebugCommands)
 				warn("Invalid command: garrison target cannot be controlled by player "+player+" (or ally): "+uneval(cmd));
@@ -473,11 +458,10 @@
 
 	"guard": function(player, cmd, data)
 	{
-		// Verify that the target can be controlled by the player or is mutualAlly
-		if (!CanControlUnitOrIsAlly(cmd.target, player, data.controlAllUnits))
+		if (!IsOwnedByPlayerOrMutualAlly(cmd.target, player, data.controlAllUnits))
 		{
 			if (g_DebugCommands)
-				warn("Invalid command: guard/escort target cannot be controlled by player "+player+": "+uneval(cmd));
+				warn("Invalid command: Guard/escort target is not owned by player " + player + " or ally thereof: " + uneval(cmd));
 			return;
 		}
 
@@ -495,8 +479,7 @@
 
 	"unload": function(player, cmd, data)
 	{
-		// Verify that the building can be controlled by the player or is mutualAlly
-		if (!CanControlUnitOrIsAlly(cmd.garrisonHolder, player, data.controlAllUnits))
+		if (!CanPlayerOrAllyControlUnit(cmd.garrisonHolder, player, data.controlAllUnits))
 		{
 			if (g_DebugCommands)
 				warn("Invalid command: unload target cannot be controlled by player "+player+" (or ally): "+uneval(cmd));
@@ -876,6 +859,27 @@
 }
 
 /**
+ * Sends a GUI notification about entities that can't be controlled.
+ * @param {number} player - The player-ID of the player that needs to receive this message.
+ */
+function notifyOrderFailure(entity, player)
+{
+	let cmpIdentity = Engine.QueryInterface(entity, IID_Identity);
+	if (!cmpIdentity)
+		return;
+
+	let cmpGUIInterface = Engine.QueryInterface(SYSTEM_ENTITY, IID_GuiInterface);
+	cmpGUIInterface.PushNotification({
+		"type": "text",
+		"players": [player],
+		"message": sprintf(markForTranslation("%(unit)s can't be controlled."), {
+			"unit": cmpIdentity.GetGenericName()
+		}),
+		"translateMessage": true
+	});
+}
+
+/**
  * Get some information about the formations used by entities.
  * The entities must have a UnitAI component.
  */
@@ -1661,27 +1665,55 @@
 
 /**
  * Check if player can control this entity
- * returns: true if the entity is valid and owned by the player
+ * returns: true if the entity is owned by the player and controllable
  *          or control all units is activated, else false
  */
 function CanControlUnit(entity, player, controlAll)
 {
-	return IsOwnedByPlayer(player, entity) || controlAll;
+	let cmpIdentity = Engine.QueryInterface(entity, IID_Identity);
+	let canBeControlled = IsOwnedByPlayer(player, entity) &&
+		(!cmpIdentity || cmpIdentity.IsControllable()) ||
+		controlAll;
+
+	if (!canBeControlled)
+		notifyOrderFailure(entity, player);
+
+	return canBeControlled;
+}
+
+/**
+ * @param {number} entity - The entityID to verify.
+ * @param {number} player - The playerID to check against.
+ * @return {boolean}.
+ */
+function IsOwnedByPlayerOrMutualAlly(entity, player)
+{
+	return IsOwnedByPlayer(player, entity) || IsOwnedByMutualAllyOfPlayer(player, entity);
 }
 
 /**
  * Check if player can control this entity
- * returns: true if the entity is valid and owned by the player
- *          or the entity is owned by an mutualAlly
- *          or control all units is activated, else false
+ * @return {boolean} - True if the entity is valid and controlled by the player
+ *          or the entity is owned by an mutualAlly and can be controlled
+ *          or control all units is activated, else false.
+ */
+function CanPlayerOrAllyControlUnit(entity, player, controlAll)
+{
+	return CanControlUnit(player, entity, controlAll) ||
+		IsOwnedByMutualAllyOfPlayer(player, entity) && CanOwnerControlEntity(entity);
+}
+
+/**
+ * @return {boolean} - Whether the owner of this entity can control the entity.
  */
-function CanControlUnitOrIsAlly(entity, player, controlAll)
+function CanOwnerControlEntity(entity)
 {
-	return IsOwnedByPlayer(player, entity) || IsOwnedByMutualAllyOfPlayer(player, entity) || controlAll;
+	let cmpOwner = QueryOwnerInterface(entity);
+	return cmpOwner && CanControlUnit(entity, cmpOwner.GetPlayerID());
 }
 
 /**
- * Filter entities which the player can control
+ * Filter entities which the player can control.
  */
 function FilterEntityList(entities, player, controlAll)
 {
@@ -1693,7 +1725,7 @@
  */
 function FilterEntityListWithAllies(entities, player, controlAll)
 {
-	return entities.filter(ent => CanControlUnitOrIsAlly(ent, player, controlAll));
+	return entities.filter(ent => CanPlayerOrAllyControlUnit(ent, player, controlAll));
 }
 
 /**