Index: ps/trunk/binaries/data/mods/public/gui/session/developer_overlay.js
===================================================================
--- ps/trunk/binaries/data/mods/public/gui/session/developer_overlay.js
+++ ps/trunk/binaries/data/mods/public/gui/session/developer_overlay.js
@@ -1,259 +0,0 @@
-function DeveloperOverlay(playerViewControl)
-{
-	this.commandHeight = 20;
-	this.displayState = false;
-	this.timeWarp = false;
-	this.controlAll = false;
-	this.playerViewControl = playerViewControl;
-	Engine.GetGUIObjectByName("devCommandsOverlay").onPress = this.toggle;
-	this.layout();
-
-	registerSimulationUpdateHandler(this.update.bind(this));
-	registerEntitySelectionChangeHandler(this.update.bind(this));
-}
-
-DeveloperOverlay.prototype.getCommands = function() {
-	return [
-		{
-			"label": translate("Control all units"),
-			"onPress": checked => {
-				Engine.PostNetworkCommand({
-					"type": "control-all",
-					"flag": checked
-				});
-			},
-			"checked": () => this.controlAll,
-		},
-		{
-			"label": translate("Change perspective"),
-			"onPress": checked => {
-				this.playerViewControl.setChangePerspective(checked);
-			},
-		},
-		{
-			"label": translate("Display selection state"),
-			"onPress": checked => {
-				this.displayState = checked;
-				this.update();
-			},
-		},
-		{
-			"label": translate("Pathfinder overlay"),
-			"onPress": checked => {
-				Engine.GuiInterfaceCall("SetPathfinderDebugOverlay", checked);
-			},
-		},
-		{
-			"label": translate("Obstruction overlay"),
-			"onPress": checked => {
-				Engine.GuiInterfaceCall("SetObstructionDebugOverlay", checked);
-			},
-		},
-		{
-			"label": translate("Unit motion overlay"),
-			"onPress": checked => {
-				g_Selection.SetMotionDebugOverlay(checked);
-			},
-		},
-		{
-			"label": translate("Range overlay"),
-			"onPress": checked => {
-				Engine.GuiInterfaceCall("SetRangeDebugOverlay", checked);
-			},
-		},
-		{
-			"label": translate("Bounding box overlay"),
-			"onPress": checked => {
-				Engine.SetBoundingBoxDebugOverlay(checked);
-			},
-		},
-		{
-			"label": translate("Restrict camera"),
-			"onPress": checked => {
-				Engine.GameView_SetConstrainCameraEnabled(checked);
-			},
-			"checked": () => Engine.GameView_GetConstrainCameraEnabled(),
-		},
-		{
-			"label": translate("Reveal map"),
-			"onPress": checked => {
-				Engine.PostNetworkCommand({
-					"type": "reveal-map",
-					"enable": checked
-				});
-			},
-			"checked": () => Engine.GuiInterfaceCall("IsMapRevealed"),
-		},
-		{
-			"label": translate("Enable time warp"),
-			"onPress": checked => {
-				this.timeWarp = checked;
-				if (checked)
-					messageBox(
-						500, 250,
-						translate("Note: time warp mode is a developer option, and not intended for use over long periods of time. Using it incorrectly may cause the game to run out of memory or crash."),
-						translate("Time warp mode"));
-				Engine.EnableTimeWarpRecording(checked ? 10 : 0);
-			},
-		},
-		{
-			"label": translate("Promote selected units"),
-			"onPress": checked => {
-				Engine.PostNetworkCommand({
-					"type": "promote",
-					"entities": g_Selection.toList()
-				});
-			},
-		},
-		{
-			"label": translate("Hierarchical pathfinder overlay"),
-			"onPress": checked => {
-				Engine.GuiInterfaceCall("SetPathfinderHierDebugOverlay", checked);
-			},
-		},
-		{
-			"label": translate("Enable culling"),
-			"onPress": checked => {
-				Engine.GameView_SetCullingEnabled(checked);
-			},
-			"checked": () => Engine.GameView_GetCullingEnabled(),
-		},
-		{
-			"label": translate("Lock cull camera"),
-			"onPress": checked => {
-				Engine.GameView_SetLockCullCameraEnabled(checked);
-			},
-			"checked": () => Engine.GameView_GetLockCullCameraEnabled(),
-		},
-		{
-			"label": translate("Display camera frustum"),
-			"onPress": checked => {
-				Engine.Renderer_SetDisplayFrustumEnabled(checked);
-			},
-			"checked": () => Engine.Renderer_GetDisplayFrustumEnabled(),
-		},
-	];
-};
-
-DeveloperOverlay.prototype.layout = function()
-{
-	for (let body of Engine.GetGUIObjectByName("dev_commands").children)
-		body.hidden = true;
-
-	let overlayHeight = 0;
-	let commands = this.getCommands();
-	for (let i = 0; i < commands.length; ++i)
-	{
-		let command = commands[i];
-
-		let body = Engine.GetGUIObjectByName("dev_command[" + i + "]");
-		let bodySize = body.size;
-		bodySize.top = i * this.commandHeight;
-		bodySize.bottom = bodySize.top + this.commandHeight;
-		body.size = bodySize;
-		body.hidden = false;
-
-		let label = Engine.GetGUIObjectByName("dev_command_label[" + i + "]");
-		label.caption = command.label;
-
-		let checkbox = Engine.GetGUIObjectByName("dev_command_checkbox[" + i + "]");
-		checkbox.onPress = function() {
-			command.onPress(checkbox.checked);
-			if (command.checked)
-				checkbox.checked = command.checked();
-		};
-
-		overlayHeight += this.commandHeight;
-	}
-
-	let overlay = Engine.GetGUIObjectByName("devCommandsOverlay");
-	let overlaySize = overlay.size;
-	overlaySize.bottom = overlaySize.top + overlayHeight;
-	overlay.size = overlaySize;
-
-	this.updateValues();
-};
-
-DeveloperOverlay.prototype.updateValues = function()
-{
-	this.getCommands().forEach((command, i) => {
-		let checkbox = Engine.GetGUIObjectByName("dev_command_checkbox[" + i + "]");
-		if (command.checked)
-			checkbox.checked = command.checked();
-	});
-};
-
-DeveloperOverlay.prototype.toggle = function()
-{
-	if (!g_GameAttributes.settings.CheatsEnabled && !g_IsReplay)
-		return;
-
-	let overlay = Engine.GetGUIObjectByName("devCommandsOverlay");
-	overlay.hidden = !overlay.hidden;
-
-	let message = overlay.hidden ?
-		markForTranslation("The Developer Overlay was closed.") :
-		markForTranslation("The Developer Overlay was opened.");
-
-	// Only players can send the simulation chat command
-	if (Engine.GetPlayerID() == -1)
-		g_Chat.submitChat(message);
-	else
-		Engine.PostNetworkCommand({
-			"type": "aichat",
-			"message": message,
-			"translateMessage": true,
-			"translateParameters": [],
-			"parameters": {}
-		});
-};
-
-DeveloperOverlay.prototype.update = function()
-{
-	let playerState = g_SimState.players[g_ViewedPlayer];
-	this.controlAll = playerState ? playerState.controlsAll : false;
-
-	this.updateValues();
-	this.updateEntityState();
-}
-
-DeveloperOverlay.prototype.updateEntityState = function()
-{
-	let debug = Engine.GetGUIObjectByName("debugEntityState");
-
-	if (!this.displayState)
-	{
-		debug.hidden = true;
-		return;
-	}
-
-	debug.hidden = false;
-
-	let conciseSimState = clone(GetSimState());
-	conciseSimState.players = "<<<omitted>>>";
-	let text = "simulation: " + uneval(conciseSimState);
-
-	let selection = g_Selection.toList();
-	if (selection.length)
-	{
-		let entState = GetEntityState(selection[0]);
-		if (entState)
-		{
-			let template = GetTemplateData(entState.template);
-			text += "\n\nentity: {\n";
-			for (let k in entState)
-				text += "  " + k + ":" + uneval(entState[k]) + "\n";
-			text += "}\n\ntemplate: " + uneval(template);
-		}
-	}
-
-	debug.caption = text.replace(/\[/g, "\\[");
-};
-
-DeveloperOverlay.prototype.isTimeWarpEnabled = function() {
-	return this.timeWarp;
-};
-
-DeveloperOverlay.prototype.isControlAll = function() {
-	return this.controlAll;
-};
Index: ps/trunk/binaries/data/mods/public/gui/session/developer_overlay.xml
===================================================================
--- ps/trunk/binaries/data/mods/public/gui/session/developer_overlay.xml
+++ ps/trunk/binaries/data/mods/public/gui/session/developer_overlay.xml
@@ -1,20 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-
-<object
-	name="devCommandsOverlay"
-	type="image"
-	sprite="sessionOverlayBackground"
-	size="100%-250 50%-200 100%-8 50%"
-	z="40"
-	hidden="true"
-	hotkey="session.devcommands.toggle"
->
-	<object name="dev_commands">
-		<repeat count="16">
-			<object name="dev_command[n]" size="0 0 100% 0">
-				<object name="dev_command_label[n]" size="0 0 100%-26 100%" type="text" style="devCommandsText"/>
-				<object name="dev_command_checkbox[n]" size="100%-24 1 100% 100%" type="checkbox" style="ModernTickBox"/>
-			</object>
-		</repeat>
-	</object>
-</object>
Index: ps/trunk/binaries/data/mods/public/gui/session/developer_overlay/DeveloperOverlay.js
===================================================================
--- ps/trunk/binaries/data/mods/public/gui/session/developer_overlay/DeveloperOverlay.js
+++ ps/trunk/binaries/data/mods/public/gui/session/developer_overlay/DeveloperOverlay.js
@@ -0,0 +1,68 @@
+/**
+ * This class stores the checkboxes that are part of the developer overlay.
+ * These checkboxes may own their own helper class instances, such as the EntityState or TimeWarp feature.
+ */
+class DeveloperOverlay
+{
+	constructor(playerViewControl, selection)
+	{
+		this.devCommandsOverlay = Engine.GetGUIObjectByName("devCommandsOverlay");
+		this.devCommandsOverlay.onPress = this.toggle.bind(this);
+
+		this.checkBoxes = this.getCheckboxNames().map((name, i) =>
+			new DeveloperOverlayCheckbox(
+				new DeveloperOverlayCheckboxes.prototype[name](playerViewControl, selection),
+				i));
+
+		this.resize();
+	}
+
+	/**
+	 * Mods may overwrite this to change the order.
+	 */
+	getCheckboxNames()
+	{
+		return Object.keys(DeveloperOverlayCheckboxes.prototype);
+	}
+
+	toggle()
+	{
+		if (g_IsNetworked && !g_GameAttributes.settings.CheatsEnabled)
+			return;
+
+		this.devCommandsOverlay.hidden = !this.devCommandsOverlay.hidden;
+		this.sendNotification();
+		this.checkBoxes.forEach(checkbox => {
+			checkbox.setHidden(this.devCommandsOverlay.hidden);
+		});
+	}
+
+	sendNotification()
+	{
+		let message = this.devCommandsOverlay.hidden ? this.CloseNotification : this.OpenNotification;
+
+		// Only players can send the simulation chat command
+		if (Engine.GetPlayerID() == -1)
+			g_Chat.submitChat(message);
+		else
+			Engine.PostNetworkCommand({
+				"type": "aichat",
+				"message": message,
+				"translateMessage": true,
+				"translateParameters": [],
+				"parameters": {}
+			});
+	}
+
+	resize()
+	{
+		let size = this.devCommandsOverlay.size;
+		size.bottom =
+			size.top +
+			this.checkBoxes.reduce((height, checkbox) => height + checkbox.getHeight(), 0);
+		this.devCommandsOverlay.size = size;
+	}
+}
+
+DeveloperOverlay.prototype.OpenNotification = markForTranslation("The Developer Overlay was opened.");
+DeveloperOverlay.prototype.CloseNotification = markForTranslation("The Developer Overlay was closed.");
Index: ps/trunk/binaries/data/mods/public/gui/session/developer_overlay/DeveloperOverlay.xml
===================================================================
--- ps/trunk/binaries/data/mods/public/gui/session/developer_overlay/DeveloperOverlay.xml
+++ ps/trunk/binaries/data/mods/public/gui/session/developer_overlay/DeveloperOverlay.xml
@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<object
+	name="devCommandsOverlay"
+	type="image"
+	sprite="sessionOverlayBackground"
+	size="100%-250 50%-200 100%-8 50%"
+	z="40"
+	hidden="true"
+	hotkey="session.devcommands.toggle"
+>
+	<repeat count="20">
+		<object name="dev_command[n]" size="0 0 100% 20" hidden="true">
+			<object name="dev_command_label[n]" size="0 0 100%-26 100%" type="text" style="devCommandsText"/>
+			<object name="dev_command_checkbox[n]" size="100%-24 1 100% 100%" type="checkbox" style="ModernTickBox"/>
+		</object>
+	</repeat>
+</object>
Index: ps/trunk/binaries/data/mods/public/gui/session/developer_overlay/DeveloperOverlayCheckbox.js
===================================================================
--- ps/trunk/binaries/data/mods/public/gui/session/developer_overlay/DeveloperOverlayCheckbox.js
+++ ps/trunk/binaries/data/mods/public/gui/session/developer_overlay/DeveloperOverlayCheckbox.js
@@ -0,0 +1,63 @@
+/**
+ * This class sets up a checkbox in the developer overlay and assigns its specific handler.
+ */
+class DeveloperOverlayCheckbox
+{
+	constructor(handler, i)
+	{
+		this.handler = handler;
+
+		this.label = Engine.GetGUIObjectByName("dev_command_label[" + i + "]");
+		this.label.caption = this.handler.label();
+
+		this.checkbox = Engine.GetGUIObjectByName("dev_command_checkbox[" + i + "]");
+		this.checkbox.onPress = this.onPress.bind(this);
+
+		this.body = Engine.GetGUIObjectByName("dev_command[" + i + "]");
+		this.resize(i);
+
+		this.updater = this.update.bind(this);
+
+		if (this.handler.checked)
+			registerPlayersInitHandler(this.updater);
+	}
+
+	onPress()
+	{
+		this.handler.onPress(this.checkbox.checked);
+
+		if (this.handler.checked)
+			this.update();
+	}
+
+	update()
+	{
+		this.checkbox.checked = this.handler.checked();
+	}
+
+	setHidden(hidden)
+	{
+		if (!this.handler.checked)
+			return;
+
+		if (hidden)
+			unregisterSimulationUpdateHandler(this.updater);
+		else
+			registerSimulationUpdateHandler(this.updater);
+	}
+
+	getHeight()
+	{
+		return this.body.size.bottom - this.body.size.top;
+	}
+
+	resize(i)
+	{
+		let size = this.body.size;
+		let height = size.bottom;
+		size.top = height * i;
+		size.bottom = height * (i + 1);
+		this.body.size = size;
+		this.body.hidden = false;
+	}
+}
Index: ps/trunk/binaries/data/mods/public/gui/session/developer_overlay/DeveloperOverlayCheckboxes.js
===================================================================
--- ps/trunk/binaries/data/mods/public/gui/session/developer_overlay/DeveloperOverlayCheckboxes.js
+++ ps/trunk/binaries/data/mods/public/gui/session/developer_overlay/DeveloperOverlayCheckboxes.js
@@ -0,0 +1,277 @@
+/**
+ * This class stores the handlers for the individual checkboxes available in the developer overlay.
+ * Such a class must have label and onPress function.
+ * If the class has a checked property, then that will be called every simulation update to
+ * synchronize the state of the checkbox (only if the developer overaly is opened).
+ */
+class DeveloperOverlayCheckboxes
+{
+}
+
+DeveloperOverlayCheckboxes.prototype.ControlAll = class
+{
+	label()
+	{
+		return translate("Control all units");
+	}
+
+	onPress(checked)
+	{
+		Engine.PostNetworkCommand({
+			"type": "control-all",
+			"flag": checked
+		});
+	}
+
+	checked()
+	{
+		let playerState = g_SimState.players[g_ViewedPlayer];
+		return playerState ? playerState.controlsAll : false;
+	}
+};
+
+DeveloperOverlayCheckboxes.prototype.ChangePerspective = class
+{
+	constructor(playerViewControl)
+	{
+		this.playerViewControl = playerViewControl;
+	}
+
+	label()
+	{
+		return translate("Change perspective");
+	}
+
+	onPress(checked)
+	{
+		this.playerViewControl.setChangePerspective(checked);
+	}
+};
+
+DeveloperOverlayCheckboxes.prototype.SelectionEntityState = class
+{
+	constructor(playerViewControl, selection)
+	{
+		this.developerOverlayEntityState = new DeveloperOverlayEntityState(selection);
+	}
+
+	label()
+	{
+		return translate("Display selection state");
+	}
+
+	onPress(checked)
+	{
+		this.developerOverlayEntityState.setEnabled(checked);
+	}
+};
+
+DeveloperOverlayCheckboxes.prototype.PathfinderOverlay = class
+{
+	label()
+	{
+		return translate("Pathfinder overlay");
+	}
+
+	onPress(checked)
+	{
+		Engine.GuiInterfaceCall("SetPathfinderDebugOverlay", checked);
+	}
+};
+
+DeveloperOverlayCheckboxes.prototype.HierarchicalPathfinderOverlay = class
+{
+	label()
+	{
+		return translate("Hierarchical pathfinder overlay");
+	}
+
+	onPress(checked)
+	{
+		Engine.GuiInterfaceCall("SetPathfinderHierDebugOverlay", checked);
+	}
+};
+
+DeveloperOverlayCheckboxes.prototype.ObstructionOverlay = class
+{
+	label()
+	{
+		return translate("Obstruction overlay");
+	}
+
+	onPress(checked)
+	{
+		Engine.GuiInterfaceCall("SetObstructionDebugOverlay", checked);
+	}
+};
+
+DeveloperOverlayCheckboxes.prototype.UnitMotionOverlay = class
+{
+	label()
+	{
+		return translate("Unit motion overlay");
+	}
+
+	onPress(checked)
+	{
+		g_Selection.SetMotionDebugOverlay(checked);
+	}
+};
+
+DeveloperOverlayCheckboxes.prototype.RangeOverlay = class
+{
+	label()
+	{
+		return translate("Range overlay");
+	}
+
+	onPress(checked)
+	{
+		Engine.GuiInterfaceCall("SetRangeDebugOverlay", checked);
+	}
+};
+
+DeveloperOverlayCheckboxes.prototype.BoundingBoxOverlay = class
+{
+	label()
+	{
+		return translate("Bounding box overlay");
+	}
+
+	onPress(checked)
+	{
+		Engine.SetBoundingBoxDebugOverlay(checked);
+	}
+};
+
+DeveloperOverlayCheckboxes.prototype.RestrictCamera = class
+{
+	label()
+	{
+		return translate("Restrict camera");
+	}
+
+	onPress(checked)
+	{
+		Engine.GameView_SetConstrainCameraEnabled(checked);
+	}
+
+	checked()
+	{
+		return Engine.GameView_GetConstrainCameraEnabled();
+	}
+};
+
+DeveloperOverlayCheckboxes.prototype.RevealMap = class
+{
+	label()
+	{
+		return translate("Reveal map");
+	}
+
+	onPress(checked)
+	{
+		Engine.PostNetworkCommand({
+			"type": "reveal-map",
+			"enable": checked
+		});
+	}
+
+	checked()
+	{
+		return Engine.GuiInterfaceCall("IsMapRevealed");
+	}
+};
+
+DeveloperOverlayCheckboxes.prototype.EnableTimeWarp = class
+{
+	constructor()
+	{
+		this.timeWarp = new TimeWarp();
+	}
+
+	label()
+	{
+		return translate("Enable time warp");
+	}
+
+	onPress(checked)
+	{
+		this.timeWarp.setEnabled(checked);
+	}
+};
+
+DeveloperOverlayCheckboxes.prototype.PromoteSelectedUnits = class
+{
+	label()
+	{
+		return translate("Promote selected units");
+	}
+
+	onPress(checked)
+	{
+		Engine.PostNetworkCommand({
+			"type": "promote",
+			"entities": g_Selection.toList()
+		});
+	}
+
+	checked()
+	{
+		return false;
+	}
+};
+
+DeveloperOverlayCheckboxes.prototype.EnableCulling = class
+{
+	label()
+	{
+		return translate("Enable culling");
+	}
+
+	onPress(checked)
+	{
+		Engine.GameView_SetCullingEnabled(checked);
+	}
+
+	checked()
+	{
+		return Engine.GameView_GetCullingEnabled();
+	}
+};
+
+DeveloperOverlayCheckboxes.prototype.LockCullCamera = class
+{
+	label()
+	{
+		return translate("Lock cull camera");
+	}
+
+	onPress(checked)
+	{
+		Engine.GameView_SetLockCullCameraEnabled(checked);
+	}
+
+	checked()
+	{
+		return Engine.GameView_GetLockCullCameraEnabled();
+	}
+};
+
+DeveloperOverlayCheckboxes.prototype.DisplayCameraFrustum = class
+{
+	label()
+	{
+		return translate("Display camera frustum");
+	}
+
+	onPress(checked)
+	{
+		Engine.Renderer_SetDisplayFrustumEnabled(checked);
+	}
+
+	checked()
+	{
+		return Engine.Renderer_GetDisplayFrustumEnabled();
+	}
+};
Index: ps/trunk/binaries/data/mods/public/gui/session/developer_overlay/DeveloperOverlayEntityState.js
===================================================================
--- ps/trunk/binaries/data/mods/public/gui/session/developer_overlay/DeveloperOverlayEntityState.js
+++ ps/trunk/binaries/data/mods/public/gui/session/developer_overlay/DeveloperOverlayEntityState.js
@@ -0,0 +1,51 @@
+/**
+ * This class manages the developer overlay which displays the state of the first selected entity.
+ */
+class DeveloperOverlayEntityState
+{
+	constructor(selection)
+	{
+		this.developerOverlayEntityState = Engine.GetGUIObjectByName("developerOverlayEntityState");
+		this.selection = selection;
+		this.updater = this.update.bind(this);
+	}
+
+	setEnabled(enabled)
+	{
+		this.developerOverlayEntityState.hidden = !enabled;
+
+		if (enabled)
+		{
+			registerSimulationUpdateHandler(this.updater);
+			registerEntitySelectionChangeHandler(this.updater);
+		}
+		else
+		{
+			unregisterSimulationUpdateHandler(this.updater);
+			unregisterEntitySelectionChangeHandler(this.updater);
+		}
+	}
+
+	update()
+	{
+		let simState = clone(g_SimState);
+		simState.players = "<<<omitted>>>";
+		let text = "simulation: " + uneval(simState);
+
+		let selection = this.selection.toList();
+		if (selection.length)
+		{
+			let entState = GetEntityState(selection[0]);
+			if (entState)
+			{
+				let template = GetTemplateData(entState.template);
+				text += "\n\nentity: {\n";
+				for (let k in entState)
+					text += "  " + k + ":" + uneval(entState[k]) + "\n";
+				text += "}\n\ntemplate: " + uneval(template);
+			}
+		}
+
+		this.developerOverlayEntityState.caption = text.replace(/\[/g, "\\[");
+	}
+}
Index: ps/trunk/binaries/data/mods/public/gui/session/developer_overlay/DeveloperOverlayEntityState.xml
===================================================================
--- ps/trunk/binaries/data/mods/public/gui/session/developer_overlay/DeveloperOverlayEntityState.xml
+++ ps/trunk/binaries/data/mods/public/gui/session/developer_overlay/DeveloperOverlayEntityState.xml
@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="utf-8"?>
+<object name="developerOverlayEntityState"
+	type="text"
+	size="0 70 80% 100%"
+	ghost="true"
+	textcolor="yellow"
+	font="mono-stroke-10"
+	hidden="true"
+/>
Index: ps/trunk/binaries/data/mods/public/gui/session/developer_overlay/TimeWarp.js
===================================================================
--- ps/trunk/binaries/data/mods/public/gui/session/developer_overlay/TimeWarp.js
+++ ps/trunk/binaries/data/mods/public/gui/session/developer_overlay/TimeWarp.js
@@ -0,0 +1,66 @@
+/**
+ * This class manages the timewarp hotkeys that allow jumping back in time and fast forwarding the game.
+ */
+class TimeWarp
+{
+	constructor()
+	{
+		this.enabled = false;
+
+		this.timewarpRewind = Engine.GetGUIObjectByName("timewarpRewind");
+		this.timewarpRewind.onPress = this.rewind.bind(this);
+
+		this.timewarpFastForward = Engine.GetGUIObjectByName("timewarpFastForward");
+		this.timewarpFastForward.onPress = this.fastForward.bind(this);
+		this.timewarpFastForward.onRelease = this.resetSpeed.bind(this);
+	}
+
+	setEnabled(enabled)
+	{
+		if (g_IsNetworked)
+			return;
+
+		this.enabled = enabled;
+
+		if (enabled)
+			messageBox(
+				500, 250,
+				translate(this.Description),
+				translate(this.Title));
+
+		Engine.EnableTimeWarpRecording(enabled ? this.NumberTurns : 0);
+	}
+
+	rewind()
+	{
+		if (this.enabled)
+			Engine.RewindTimeWarp();
+	}
+
+	fastForward()
+	{
+		if (this.enabled)
+			Engine.SetSimRate(this.FastForwardSpeed);
+	}
+
+	resetSpeed()
+	{
+		if (this.enabled)
+			Engine.SetSimRate(1);
+	}
+}
+
+/**
+ * Number of turns between snapshots.
+ */
+TimeWarp.prototype.NumberTurns = 10;
+
+/**
+ * Gamespeed used while pressing the fast forward hotkey.
+ */
+TimeWarp.prototype.FastForwardSpeed = 20;
+
+TimeWarp.prototype.Title = markForTranslation("Time warp mode");
+
+TimeWarp.prototype.Description = markForTranslation(
+	"Note: time warp mode is a developer option, and not intended for use over long periods of time. Using it incorrectly may cause the game to run out of memory or crash.");
Index: ps/trunk/binaries/data/mods/public/gui/session/developer_overlay/TimeWarp.xml
===================================================================
--- ps/trunk/binaries/data/mods/public/gui/session/developer_overlay/TimeWarp.xml
+++ ps/trunk/binaries/data/mods/public/gui/session/developer_overlay/TimeWarp.xml
@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<object>
+	<object name="timewarpRewind" hotkey="session.timewarp.rewind"/>
+	<object name="timewarpFastForward" hotkey="session.timewarp.fastforward"/>
+</object>
Index: ps/trunk/binaries/data/mods/public/gui/session/input.js
===================================================================
--- ps/trunk/binaries/data/mods/public/gui/session/input.js
+++ ps/trunk/binaries/data/mods/public/gui/session/input.js
@@ -223,12 +223,7 @@
 		return undefined;
 
 	// If the selection isn't friendly units, no action
-	var allOwnedByPlayer = selection.every(ent => {
-		var entState = GetEntityState(ent);
-		return entState && entState.player == g_ViewedPlayer;
-	});
-
-	if (!g_DeveloperOverlay.isControlAll() && !allOwnedByPlayer)
+	if (!selection.every(canControlEntity))
 		return undefined;
 
 	var target = undefined;
@@ -278,6 +273,19 @@
 	return { "type": "none", "cursor": "", "target": target };
 }
 
+function canControlEntity(ent)
+{
+	let entState = GetEntityState(ent);
+	if (!entState)
+		return false;
+
+	if (entState.player == g_ViewedPlayer)
+		return true;
+
+	let playerState = g_SimState.players[entState.player];
+	return playerState && playerState.controlsAll;
+}
+
 function tryPlaceBuilding(queued)
 {
 	if (placementSupport.mode !== "building")
@@ -786,17 +794,6 @@
 	if (ev.hotkey === undefined)
 		ev.hotkey = null;
 
-	// Handle the time-warp testing features, restricted to single-player
-	if (!g_IsNetworked && g_DeveloperOverlay.isTimeWarpEnabled())
-	{
-		if (ev.type == "hotkeydown" && ev.hotkey == "session.timewarp.fastforward")
-			Engine.SetSimRate(20.0);
-		else if (ev.type == "hotkeyup" && ev.hotkey == "session.timewarp.fastforward")
-			Engine.SetSimRate(1.0);
-		else if (ev.type == "hotkeyup" && ev.hotkey == "session.timewarp.rewind")
-			Engine.RewindTimeWarp();
-	}
-
 	if (ev.hotkey == "session.highlightguarding")
 	{
 		g_ShowGuarding = (ev.type == "hotkeydown");
Index: ps/trunk/binaries/data/mods/public/gui/session/selection.js
===================================================================
--- ps/trunk/binaries/data/mods/public/gui/session/selection.js
+++ ps/trunk/binaries/data/mods/public/gui/session/selection.js
@@ -214,8 +214,10 @@
 {
 	this.checkRenamedEntities();
 
+	let controlsAll = g_SimState.players[g_ViewedPlayer] && g_SimState.players[g_ViewedPlayer].controlsAll;
+	let removeOwnerChanges = !g_IsObserver && !controlsAll && this.toList().length > 1;
+
 	let changed = false;
-	let removeOwnerChanges = !g_IsObserver && !g_DeveloperOverlay.isControlAll() && this.toList().length > 1;
 
 	for (let ent in this.selected)
 	{
@@ -377,6 +379,9 @@
 	return undefined;
 };
 
+/**
+ * TODO: This array should not be recreated every call
+ */
 EntitySelection.prototype.toList = function()
 {
 	let ents = [];
Index: ps/trunk/binaries/data/mods/public/gui/session/session.js
===================================================================
--- ps/trunk/binaries/data/mods/public/gui/session/session.js
+++ ps/trunk/binaries/data/mods/public/gui/session/session.js
@@ -11,6 +11,7 @@
 const g_VictoryConditions = g_Settings && g_Settings.VictoryConditions;
 
 var g_Chat;
+var g_DeveloperOverlay;
 var g_DiplomacyColors;
 var g_DiplomacyDialog;
 var g_GameSpeedControl;
@@ -107,8 +108,6 @@
  */
 var g_PlayerAssignments;
 
-var g_DeveloperOverlay;
-
 /**
  * Whether the entire UI should be hidden (useful for promotional screenshots).
  * Can be toggled with a hotkey.
@@ -134,22 +133,22 @@
  * These handlers are called each time a new turn was simulated.
  * Use this as sparely as possible.
  */
-var g_SimulationUpdateHandlers = [];
+var g_SimulationUpdateHandlers = new Set();
 
 /**
  * These handlers are called after the player states have been initialized.
  */
-var g_PlayersInitHandlers = [];
+var g_PlayersInitHandlers = new Set();
 
 /**
  * These handlers are called when a player has been defeated or won the game.
  */
-var g_PlayerFinishedHandlers = [];
+var g_PlayerFinishedHandlers = new Set();
 
 /**
  * These events are fired whenever the player added or removed entities from the selection.
  */
-var g_EntitySelectionChangeHandlers = [];
+var g_EntitySelectionChangeHandlers = new Set();
 
 /**
  * These events are fired when the user has performed a hotkey assignment change.
@@ -281,7 +280,7 @@
 	g_PlayerViewControl.registerViewedPlayerChangeHandler(resetTemplates);
 
 	g_Chat = new Chat(g_PlayerViewControl);
-	g_DeveloperOverlay = new DeveloperOverlay(g_PlayerViewControl);
+	g_DeveloperOverlay = new DeveloperOverlay(g_PlayerViewControl, g_Selection);
 	g_DiplomacyDialog = new DiplomacyDialog(g_PlayerViewControl, g_DiplomacyColors);
 	g_GameSpeedControl = new GameSpeedControl(g_PlayerViewControl);
 	g_MiniMapPanel = new MiniMapPanel(g_PlayerViewControl, g_DiplomacyColors, g_WorkerTypes);
@@ -323,22 +322,32 @@
 
 function registerPlayersInitHandler(handler)
 {
-	g_PlayersInitHandlers.push(handler);
+	g_PlayersInitHandlers.add(handler);
 }
 
 function registerPlayersFinishedHandler(handler)
 {
-	g_PlayerFinishedHandlers.push(handler);
+	g_PlayerFinishedHandlers.add(handler);
 }
 
 function registerSimulationUpdateHandler(handler)
 {
-	g_SimulationUpdateHandlers.push(handler);
+	g_SimulationUpdateHandlers.add(handler);
+}
+
+function unregisterSimulationUpdateHandler(handler)
+{
+	g_SimulationUpdateHandlers.delete(handler);
 }
 
 function registerEntitySelectionChangeHandler(handler)
 {
-	g_EntitySelectionChangeHandlers.push(handler);
+	g_EntitySelectionChangeHandlers.add(handler);
+}
+
+function unregisterEntitySelectionChangeHandler(handler)
+{
+	g_EntitySelectionChangeHandlers.delete(handler);
 }
 
 function registerHotkeyChangeHandler(handler)
Index: ps/trunk/binaries/data/mods/public/gui/session/session.xml
===================================================================
--- ps/trunk/binaries/data/mods/public/gui/session/session.xml
+++ ps/trunk/binaries/data/mods/public/gui/session/session.xml
@@ -5,6 +5,7 @@
 <script directory="gui/common/"/>
 <script directory="gui/session/"/>
 <script directory="gui/session/chat/"/>
+<script directory="gui/session/developer_overlay/"/>
 <script directory="gui/session/diplomacy/"/>
 <script directory="gui/session/diplomacy/playercontrols/"/>
 <script directory="gui/session/minimap/"/>
@@ -78,20 +79,11 @@
 		<object name="chatText" size="3 1 100%-1 100%-1" type="text" style="chatPanelOverlay" ghost="true"/>
 	</object>
 
-	<!-- Entity selection state text -->
-	<object name="debugEntityState"
-		type="text"
-		size="0 70 80% 100%"
-		ghost="true"
-		textcolor="yellow"
-		font="mono-stroke-10"
-	/>
-
 	<include directory="gui/session/chat/"/>
+	<include directory="gui/session/developer_overlay/"/>
 	<include directory="gui/session/dialogs/"/>
 	<include directory="gui/session/diplomacy/"/>
 	<include directory="gui/session/objectives/"/>
-	<include file="gui/session/developer_overlay.xml"/>
 	<include file="gui/session/GameSpeedControl.xml"/>
 	<include file="gui/session/TopPanel.xml"/>
 	<include file="gui/session/trade/TradeDialog.xml"/>
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
@@ -1465,7 +1465,8 @@
  */
 function isUndeletable(entState)
 {
-	if (g_DeveloperOverlay.isControlAll())
+	let playerState = g_SimState.players[entState.player];
+	if (playerState && playerState.controlsAll)
 		return false;
 
 	if (entState.resourceSupply && entState.resourceSupply.killBeforeGather)