diff --git a/binaries/data/mods/public/gui/session/session.js b/binaries/data/mods/public/gui/session/session.js
index 8ecf776ad0..a32b36931d 100644
--- a/binaries/data/mods/public/gui/session/session.js
+++ b/binaries/data/mods/public/gui/session/session.js
@@ -77,6 +77,10 @@ function init(initData, hotloadData)
 	getGUIObjectByName("civIcon").sprite = "stretched:"+g_CivData[g_Players[Engine.GetPlayerID()].civ].Emblem;
 	initMenuPosition(); // set initial position
 
+	// If in Atlas editor, disable the exit button
+	if (Engine.IsAtlasRunning())
+		getGUIObjectByName("menuExitButton").enabled = false;
+
 	if (hotloadData)
 	{
 		g_Selection.selected = hotloadData.selection;
@@ -230,9 +234,20 @@ function checkPlayerState()
 			closeMenu();
 			closeOpenDialogs();
 
-			var btCaptions = ["Yes", "No"];
-			var btCode = [leaveGame, null];
-			messageBox(400, 200, "Do you want to quit?", "DEFEATED!", 0, btCaptions, btCode);
+			if (Engine.IsAtlasRunning())
+			{
+				// If we're in Atlas, we can't leave the game
+				var btCaptions = ["OK"];
+				var btCode = [null];
+				var message = "Press OK to continue";
+			}
+			else
+			{
+				var btCaptions = ["Yes", "No"];
+				var btCode = [leaveGame, null];
+				var message = "Do you want to quit?";
+			}
+			messageBox(400, 200, message, "DEFEATED!", 0, btCaptions, btCode);
 		}
 		else if (playerState.state == "won")
 		{
@@ -245,9 +260,20 @@ function checkPlayerState()
 			if (!getGUIObjectByName("devCommandsRevealMap").checked)
 				getGUIObjectByName("devCommandsRevealMap").checked = true;
 
-			var btCaptions = ["Yes", "No"];
-			var btCode = [leaveGame, null];
-			messageBox(400, 200, "Do you want to quit?", "VICTORIOUS!", 0, btCaptions, btCode);
+			if (Engine.IsAtlasRunning())
+			{
+				// If we're in Atlas, we can't leave the game
+				var btCaptions = ["OK"];
+				var btCode = [null];
+				var message = "Press OK to continue";
+			}
+			else
+			{
+				var btCaptions = ["Yes", "No"];
+				var btCode = [leaveGame, null];
+				var message = "Do you want to quit?";
+			}
+			messageBox(400, 200, message, "VICTORIOUS!", 0, btCaptions, btCode);
 		}
 	}
 }
diff --git a/source/gui/scripting/ScriptFunctions.cpp b/source/gui/scripting/ScriptFunctions.cpp
index f0be317d0b..711cd41648 100644
--- a/source/gui/scripting/ScriptFunctions.cpp
+++ b/source/gui/scripting/ScriptFunctions.cpp
@@ -43,6 +43,7 @@
 #include "ps/UserReport.h"
 #include "ps/GameSetup/Atlas.h"
 #include "ps/GameSetup/Config.h"
+#include "tools/atlas/GameInterface/GameLoop.h"
 
 #include "simulation2/Simulation2.h"
 #include "simulation2/components/ICmpAIManager.h"
@@ -370,6 +371,11 @@ bool AtlasIsAvailable(void* UNUSED(cbdata))
 	return ATLAS_IsAvailable();
 }
 
+bool IsAtlasRunning(void* UNUSED(cbdata))
+{
+	return (g_AtlasGameLoop && g_AtlasGameLoop->running);
+}
+
 CScriptVal LoadMapSettings(void* cbdata, VfsPath pathname)
 {
 	CGUIManager* guiManager = static_cast<CGUIManager*> (cbdata);
@@ -613,6 +619,7 @@ void GuiScriptingInit(ScriptInterface& scriptInterface)
 	scriptInterface.RegisterFunction<void, std::string, &OpenURL>("OpenURL");
 	scriptInterface.RegisterFunction<void, &RestartInAtlas>("RestartInAtlas");
 	scriptInterface.RegisterFunction<bool, &AtlasIsAvailable>("AtlasIsAvailable");
+	scriptInterface.RegisterFunction<bool, &IsAtlasRunning>("IsAtlasRunning");
 	scriptInterface.RegisterFunction<CScriptVal, VfsPath, &LoadMapSettings>("LoadMapSettings");
 	scriptInterface.RegisterFunction<CScriptVal, &GetMapSettings>("GetMapSettings");
 	scriptInterface.RegisterFunction<void, entity_id_t, &CameraFollow>("CameraFollow");
diff --git a/source/tools/atlas/GameInterface/GameLoop.cpp b/source/tools/atlas/GameInterface/GameLoop.cpp
index 4a01a08373..dc07ca62fb 100644
--- a/source/tools/atlas/GameInterface/GameLoop.cpp
+++ b/source/tools/atlas/GameInterface/GameLoop.cpp
@@ -309,6 +309,7 @@ bool BeginAtlas(const CmdLineArgs& args, const DllLoader& dll)
 	Atlas_SetConfigDirectory(paths.Config().string().c_str());
 
 	// Run the engine loop in a new thread
+	g_AtlasGameLoop->running = true;
 	pthread_t engineThread;
 	pthread_create(&engineThread, NULL, RunEngine, reinterpret_cast<void*>(const_cast<CmdLineArgs*>(&args)));
 
diff --git a/source/tools/atlas/GameInterface/GameLoop.h b/source/tools/atlas/GameInterface/GameLoop.h
index 91d176ff9a..9dc702c231 100644
--- a/source/tools/atlas/GameInterface/GameLoop.h
+++ b/source/tools/atlas/GameInterface/GameLoop.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2009 Wildfire Games.
+/* Copyright (C) 2012 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -26,6 +26,8 @@ class AtlasView;
 
 struct GameLoopState
 {
+	GameLoopState() : running(false) {};
+
 	CmdLineArgs args;
 
 	bool running; // whether the Atlas game loop is still running