diff --git a/phpgwapi/js/jsapi/egw.js b/phpgwapi/js/jsapi/egw.js
index bf4af9a0ac..52df3bc439 100644
--- a/phpgwapi/js/jsapi/egw.js
+++ b/phpgwapi/js/jsapi/egw.js
@@ -25,5 +25,6 @@
 	egw_files;
 	egw_json;
 	egw_tooltip;
+	egw_css;
 */
 
diff --git a/phpgwapi/js/jsapi/egw_core.js b/phpgwapi/js/jsapi/egw_core.js
index f120f0765a..332c9df663 100644
--- a/phpgwapi/js/jsapi/egw_core.js
+++ b/phpgwapi/js/jsapi/egw_core.js
@@ -12,14 +12,14 @@
 
 "use strict";
 
-var egw;
-
 /**
  * This code setups the egw namespace and adds the "extend" function, which is
  * used by extension modules to inject their content into the egw object.
  */
 (function(_parent) {
 
+	var instanceUid = 0;
+
 	// Some local functions for cloning and merging javascript objects
 	function cloneObject(_obj) {
 		var result = {};
@@ -40,54 +40,170 @@ var egw;
 		}
 	}
 
-	function createEgwInstance(_egw, _modules, _list, _app, _window)
+	/**
+	 * The getAppModules function returns all application specific api modules
+	 * for the given application. If those application specific api instances
+	 * were not created yet, the functions creates them.
+	 *
+	 * @param _egw is a reference to the global _egw instance and is passed as
+	 * 	a context to the module instance.
+	 * @param _modules is the hash map which contains all module descriptors.
+	 * @param _moduleInstances is the the object which contains the application
+	 * 	and window specific module instances.
+	 * @param _app is the application for which the module instances should get
+	 * 	created.
+	 */
+	function getAppModules(_egw, _modules, _moduleInstances, _app)
+	{
+		// Check whether the application specific modules for that instance
+		// already exists, if not, create it
+		if (typeof _moduleInstances.app[_app] === 'undefined')
+		{
+			var modInsts = {};
+
+			// Otherwise create the application specific instances
+			for (var key in _modules)
+			{
+				var mod = _modules[key];
+				if (mod.flags === _egw.MODULE_APP_LOCAL)
+				{
+					modInsts[key] = mod.code.call(_egw, _app, window);
+				}
+			}
+
+			_moduleInstances.app[_app] = modInsts;
+		}
+
+		return _moduleInstances.app[_app];
+	}
+
+	/**
+	 * The getWndModules function returns all window specific api modules for
+	 * the given window. If those window specific api instances were not created
+	 * yet, the functions creates them.
+	 *
+	 * @param _egw is a reference to the global _egw instance and is passed as
+	 * 	a context to the module instance.
+	 * @param _modules is the hash map which contains all module descriptors.
+	 * @param _moduleInstances is the the object which contains the application
+	 * 	and window specific module instances.
+	 * @param _wnd is the window for which the module instances should get
+	 * 	created.
+	 */
+	function getWndModules(_egw, _modules, _moduleInstances, _window)
+	{
+		// Search for the specific window instance
+		for (var i = 0; i < _moduleInstances.wnd.length; i++)
+		{
+			var descr = _moduleInstances.wnd[i];
+
+			if (descr.window === _window)
+			{
+				return descr.modules;
+			}
+		}
+
+		// If none was found, create the slot
+		var mods = {};
+		_moduleInstances.wnd.push({
+			'window': _window,
+			'modules': mods
+		});
+
+		// Otherwise create the window specific instances
+		for (var key in _modules)
+		{
+			var mod = _modules[key];
+			if (mod.flags === _egw.MODULE_WND_LOCAL)
+			{
+				mods[key] = mod.code.call(_egw, null, _window);
+			}
+		}
+
+		return mods;
+	}
+
+	/**
+	 * Creates an api instance for the given application and the given window.
+	 *
+	 * @param _egw is the global _egw instance which should be used.
+	 * @param _modules is the hash map which contains references to all module
+	 * 	descriptors.
+	 * @param _moduleInstances is the the object which contains the application
+	 * 	and window specific module instances.
+	 * @param _list is the overall instances list, to which the module should be
+	 * 	added.
+	 * @param _app is the application for which the instance should be created.
+	 * @param _wnd is the window for which the instance should be created.
+	 */
+	function createEgwInstance(_egw, _modules, _moduleInstances, _list, _app,
+			_window)
 	{
 		// Clone the global object
 		var instance = cloneObject(_egw);
 
-		// Let "_window" be exactly null, if it evaluates to false
+		// Let "_window" and "_app" be exactly null, if it evaluates to false
 		_window = _window ? _window : null;
+		_app = _app ? _app : null;
 
 		// Set the application name and the window the API instance belongs to
-		instance.appName = _app ? _app : null;
+		instance.appName = _app;
 		instance.window = _window;
 
-		// Insert the newly created instance into the instances list
+		// Push the newly created instance onto the instance list
 		_list.push({
+			'instance': instance,
 			'window': _window,
-			'app': _app,
-			'instance': instance
+			'app': _app
 		});
 
-		// Re-instanciate all modules which are marked as "local"
-		for (var key in _modules)
+		// Merge either the application specific and/or the window specific
+		// module instances into the new instance
+		if (_app)
 		{
-			// Get the module object
-			var mod = _modules[key];
+			var appModules = getAppModules(_egw, _modules, _moduleInstances,
+				_app);
 
-			if (mod.flags !== _egw.MODULE_GLOBAL)
+			for (var key in appModules)
 			{
-				// If the module is marked as application local and an
-				// application instance is given or if the module is marked as
-				// window local and a window instance is given, re-instanciate
-				// this module.
-				if (((mod.flags & _egw.MODULE_APP_LOCAL) && (_app)) ||
-				    ((mod.flags & _egw.MODULE_WND_LOCAL) && (_window)))
-				{
-					var extension = mod.code.call(instance, instance,
-						_window ? _window : window);
-					mergeObjects(instance, extension);
-				}
+				mergeObjects(instance, appModules[key]);
 			}
 		}
 
+		if (_window)
+		{
+			var wndModules = getWndModules(_egw, _modules, _moduleInstances,
+				_window);
+
+			for (var key in wndModules)
+			{
+				mergeObjects(instance, wndModules[key]);
+			}
+		}
+
+		// Return the new api instance
 		return instance;
 	}
 
-	function getEgwInstance(_egw, _modules, _instances, _app, _window)
+	/**
+	 * Returns a egw instance for the given application and the given window. If
+	 * the instance does not exist now, the instance will be created.
+	 *
+	 * @param _egw is the global _egw instance which should be used.
+	 * @param _modules is the hash map which contains references to all module
+	 * 	descriptors.
+	 * @param _moduleInstances is the the object which contains the application
+	 * 	and window specific module instances.
+	 * @param _list is the overall instances list, to which the module should be
+	 * 	added.
+	 * @param _app is the application for which the instance should be created.
+	 * @param _wnd is the window for which the instance should be created.
+	 */
+	function getEgwInstance(_egw, _modules, _moduleInstances, _instances, _app,
+		_window)
 	{
 		// Generate the hash key for the instance descriptor object
-		var hash = _app ? _app : '[global]';
+		var hash = _app ? _app : '~global~';
 
 		// Let "_window" be exactly null, if it evaluates to false
 		_window = _window ? _window : null;
@@ -96,8 +212,8 @@ var egw;
 		if (typeof _instances[hash] === 'undefined')
 		{
 			_instances[hash] = [];
-			return createEgwInstance(_egw, _modules, _instances[hash], _app,
-				_window);
+			return createEgwInstance(_egw, _modules, _moduleInstances, 
+				_instances[hash], _app, _window);
 		}
 		else
 		{
@@ -114,44 +230,118 @@ var egw;
 
 		// If we're still here, no API instance for the given window has been
 		// found -- create a new entry
-		return createEgwInstance(_egw, _modules, _instances[hash], _app, _window);
+		return createEgwInstance(_egw, _modules, _moduleInstances, 
+			_instances[hash], _app, _window);
 	}
 
-	function cleanupEgwInstances(_instances)
+	function cleanupEgwInstances(_instances, _moduleInstances)
 	{
-		// Iterate over the egw instances and check whether the window they
-		// correspond to is still open.
-		for (var key in _instances)
+		function deleteClosedWindows(_arr)
 		{
-			for (var i = _instances[key].length - 1; i >= 0; i--)
+			for (var i = _arr.length - 1; i >= 0; i--)
 			{
-				// Get the instance descriptor
-				var instDescr = _instances[key][i];
-
-				// Check whether the window this API instance belongs to is
-				// still opened. If not, remove the API instance.
-				if (instDescr.window && instDescr.window.closed)
+				if (_arr[i].window && _arr[i].window.closed)
 				{
-					_instances[key].splice(i, 1)
+					_arr.splice(i, 1)
 				}
 			}
+		}
 
-			// If all instances for the current hash have been deleted, delete
-			// the hash entry itself
+		// Iterate over the instances
+		for (var key in _instances)
+		{
+			// Delete all entries corresponding to closed windows
+			deleteClosedWindows(_instances[key]);
+
+			// Delete the complete instance key if the array is empty
 			if (_instances[key].length === 0)
 			{
 				delete _instances[key];
 			}
 		}
+
+		// Delete all entries corresponding to non existing elements in the
+		// module instances
+		deleteClosedWindows(_moduleInstances.wnd);
+	}
+
+	function mergeGlobalModule(_module, _code, _instances, _moduleInstances)
+	{
+		// Generate the global extension
+		var globalExtension = _code.call(egw, null, window);
+
+		for (var key in _instances)
+		{
+			for (var i = 0; i < _instances[key].length; i++)
+			{
+				mergeObjects(_instances[key][i].instance,
+						globalExtension);
+			}
+		}
+	}
+
+	function mergeAppLocalModule(_module, _code, _instances, _moduleInstances)
+	{
+		// Generate the global extension
+		var globalExtension = _code.call(egw, null, window);
+
+		// Merge the extension into the global instances
+		for (var i = 0; i < _instances['~global~'].length; i++)
+		{
+			mergeObjects(_instances['~global~'][i].instance, globalExtension);
+		}
+
+		for (var key in _moduleInstances.app)
+		{
+			// Create the application specific instance and
+			// store it in the module instances
+			var appExtension = _code.call(egw, key, window);
+			_moduleInstances.app[key][_module] = appExtension;
+
+			// Merge the extension into all instances for
+			// the current application
+			for (var i = 0; i < _instances[key].length; i++)
+			{
+				mergeObjects(_instances[key][i].instance, appExtension);
+			}
+		}
+	}
+
+	function mergeWndLocalModule(_module, _code, _instances, _moduleInstances)
+	{
+		// Iterate over all existing windows
+		for (var i = 0; i < _moduleInstances.wnd.length; i++)
+		{
+			var wnd = _moduleInstances.wnd[i].window;
+
+			// Create the window specific instance and
+			// register it.
+			var wndExtension = _code.call(egw, null, wnd);
+			_moduleInstances.wnd[i].modules[_module] = wndExtension;
+
+			// Extend all existing instances which are using
+			// this window.
+			for (var key in _instances)
+			{
+				for (var j = 0; j < _instances[key].length; j++)
+				{
+					if (_instances[key][j].window === wnd)
+					{
+						mergeObjects(_instances[key][j].instance,
+								wndExtension);
+					}
+				}
+			}
+		}
 	}
 
 	if (window.opener && typeof window.opener.egw !== 'undefined')
 	{
-		egw = window.opener.egw;
+		this['egw'] = window.opener.egw;
 	}
 	else if (window.top && typeof window.top.egw !== 'undefined')
 	{
-		egw = window.top.egw;
+		this['egw'] = window.top.egw;
 	}
 	else
 	{
@@ -166,16 +356,13 @@ var egw;
 		 */
 		var modules = {};
 
+		var moduleInstances = {
+			'app': {},
+			'wnd': []
+		}
+
 		/**
-		 * instances contains all api instances. These are organized as a hash
-		 * of the form _app + _window.location. For each of these hashes a list
-		 * of instances is stored, where the instance itself is an entry of the
-		 * form
-		 * 	{
-		 * 		instance: <EGW_API_OBJECT>,
-		 * 		app: <APPLICATION NAME>,
-		 * 		window: <WINDOW REFERENCE>
-		 * 	}
+		 * instances contains references to all created instances.
 		 */
 		var instances = {};
 
@@ -183,7 +370,9 @@ var egw;
 		 * Set a interval which is used to cleanup unused API instances all 10
 		 * seconds.
 		 */
-		window.setInterval(function() {cleanupEgwInstances(instances);}, 10000);
+		window.setInterval(function() {
+			cleanupEgwInstances(instances, moduleInstances);
+		}, 10000);
 
 		/**
 		 * The egw function returns an instance of the client side api. If no
@@ -194,10 +383,10 @@ var egw;
 		 * has to preceed the window object reference. If no window object is
 		 * given, the root window will be used.
 		 */
-		egw = function() {
+		var egw = function() {
 
 			// Get the window/app reference
-			var _app = "";
+			var _app = null;
 			var _window = window;
 
 			switch (arguments.length)
@@ -227,7 +416,8 @@ var egw;
 			}
 
 			// Generate an API instance
-			return getEgwInstance(egw, modules, instances, _app, _window);
+			return getEgwInstance(egw, modules, moduleInstances, instances,
+					_app, _window);
 		}
 
 		var globalEgw = {
@@ -236,21 +426,21 @@ var egw;
 			 * The MODULE_GLOBAL flag describes a module as global. A global
 			 * module always works on the same data.
 			 */
-			MODULE_GLOBAL: 0x00,
+			MODULE_GLOBAL: 0,
 
 			/**
 			 * The MODULE_APP_LOCAL flag is used to describe a module as local
 			 * for each application. Each time an api object is requested for
 			 * another application, the complete module gets recreated.
 			 */
-			MODULE_APP_LOCAL: 0x01,
+			MODULE_APP_LOCAL: 1,
 
 			/**
 			 * The MODULE_WND_LOCAL flag is used to describe a module as local
 			 * for each window. Each time an api object is requested for another
 			 * window, the complete module gets recreated.
 			 */
-			MODULE_WND_LOCAL: 0x02,
+			MODULE_WND_LOCAL: 2,
 
 			/**
 			 * Name of the application the egw object belongs to.
@@ -292,7 +482,8 @@ var egw;
 			 * @param _module should be a string containing the name of the new
 			 * 	module.
 			 * @param _flags specifies whether the extension should be treated
-			 * 	as a local or a global module.
+			 * 	as a local or a global module. May be one of egw.MODULE_GLOBAL,
+			 * 	MODULE_APP_LOCAL or MODULE_WND_LOCAL.
 			 * @param _code should be a function, which returns an object that
 			 * 	should extend the egw object.
 			 */
@@ -308,33 +499,33 @@ var egw;
 						'name': _module
 					};
 
-					// Generate the global extension
-					var globalExtension = _code.call(egw, egw, window);
-
-					// Merge the global extension into the egw function
-					mergeObjects(egw, globalExtension);
-
-					// Iterate over the instances and merge the modules into
-					// them
-					for (var key in instances)
+					// Create new app/module specific instances for the new
+					// module and merge the new module into all created
+					// instances
+					switch (_flags)
 					{
-						for (var i = 0; i < instances[key].length; i++)
-						{
-							// Get the instance descriptor
-							var instDescr = instances[key][i];
+						// Easiest case -- simply merge the extension into all
+						// instances
+						case egw.MODULE_GLOBAL:
+							mergeGlobalModule(_module, _code, instances,
+									moduleInstances);
+							break;
 
-							// Merge the module into the instance
-							if (_flags !== egw.MODULE_GLOBAL)
-							{
-								mergeObjects(instDescr.instance, _code.call(
-									instDescr.instance, instDescr.instance,
-									instDescr.window ? instDescr.window : window));
-							}
-							else
-							{
-								mergeObjects(instDescr.instance, globalExtension);
-							}
-						}
+						// Create new application specific instances and merge
+						// those into all api instances for that application
+						case egw.MODULE_APP_LOCAL:
+							mergeAppLocalModule(_module, _code, instances,
+									moduleInstances);
+							break;
+
+
+						// Create new window specific instances for each window
+						// and merge those into all api instances for that
+						// window
+						case egw.MODULE_WND_LOCAL:
+							mergeWndLocalModule(_module, _code, instances,
+									moduleInstances);
+							break;
 					}
 				}
 			},
@@ -344,13 +535,33 @@ var egw;
 			},
 
 			dumpInstances: function() {
-				return instances;
+				return {
+					'instances': instances,
+					'moduleInstances': moduleInstances
+				}
 			}
 
 		};
 
 		// Merge the globalEgw functions into the egw object.
 		mergeObjects(egw, globalEgw);
-	}
-})();
+
+		// Create the entry for the root window in the module instances
+		moduleInstances.wnd.push({
+			'window': window,
+			'modules': []
+		});
+
+		// Create the entry for the global window in the instances and register
+		// the global instance there
+		instances['~global~'] = [{
+			'window': window,
+			'instance': egw,
+			'app': null
+		}];
+
+		// Publish the egw object
+		this['egw'] = egw;
+	}
+}).call(window);
 
diff --git a/phpgwapi/js/jsapi/egw_css.js b/phpgwapi/js/jsapi/egw_css.js
new file mode 100644
index 0000000000..1faa3d186c
--- /dev/null
+++ b/phpgwapi/js/jsapi/egw_css.js
@@ -0,0 +1,94 @@
+/**
+ * eGroupWare eTemplate2 - Stylesheet class
+ *
+ * @license http://opensource.org/licenses/gpl-license.php GPL - GNU General Public License
+ * @package etemplate
+ * @subpackage api
+ * @link http://www.egroupware.org
+ * @author Andreas Stöckel
+ * @copyright Stylite 2011
+ * @version $Id$
+ */
+
+"use strict"
+
+/*egw:uses
+	egw_core;
+*/
+
+egw.extend('css', egw.MODULE_WND_LOCAL, function(_egw, _wnd) {
+
+	/**
+	 * Assoziative array which stores the current css rule for a given selector.
+	 */
+	var selectors = {};
+
+	/**
+	 * Variable used to calculate unique id for the selectors.
+	 */
+	var selectorCount = 0;
+
+	// Generate a style tag, which will be used to hold the newly generated css
+	// rules.
+	var style = _wnd.document.createElement('style');
+	_wnd.document.getElementsByTagName('head')[0].appendChild(style);
+
+	// Obtain the reference to the styleSheet object of the generated style tag
+	var sheet = style.sheet ? style.sheet : style.styleSheet;
+
+	return {
+		/**
+		 * The css function can be used to introduce a rule for the given css
+		 * selector. So you're capable of adding new custom css selector while
+		 * runtime and also update them.
+		 *
+		 * @param _selector is the css select which can be used to apply the
+		 * 	stlyes to the html elements.
+		 * @param _rule is the rule which should be connected to the selector.
+		 * 	if empty or omitted, the given selector gets removed.
+		 */
+		css: function(_selector, _rule) {
+			// Set the current index to the maximum index
+			var index = selectorCount;
+
+			// Remove any existing rule first, of no rule exists for the
+			if (typeof selectors[_selector] !== "undefined")
+			{
+				// Store the old index
+				index = selectors[_selector];
+				if (typeof sheet.removeRule !== "undefined")
+				{
+					sheet.removeRule(index);
+				}
+				else
+				{
+					sheet.deleteRule(index);
+				}
+
+				delete (selectors[_selector]);
+			}
+			else
+			{
+				selectorCount++;
+			}
+
+			if (_rule)
+			{
+				// Add the rule to the stylesheet
+				if (typeof sheet.addRule !== "undefined")
+				{
+					sheet.addRule(_selector, _rule, index);
+				}
+				else
+				{
+					sheet.insertRule(_selector + "{" + _rule + "}", index);
+				}
+
+				// Store the new index
+				selectors[_selector] = index;
+			}
+		}
+	}
+
+});
+
diff --git a/phpgwapi/js/jsapi/egw_debug.js b/phpgwapi/js/jsapi/egw_debug.js
index d7210ef849..1893e77dcd 100644
--- a/phpgwapi/js/jsapi/egw_debug.js
+++ b/phpgwapi/js/jsapi/egw_debug.js
@@ -16,7 +16,7 @@
 	egw_core;
 */
 
-egw.extend('debug', egw.MODULE_GLOBAL, function(_egw, _wnd) {
+egw.extend('debug', egw.MODULE_GLOBAL, function(_app, _wnd) {
 
 	/**
 	 * DEBUGLEVEL specifies which messages are printed to the console.
diff --git a/phpgwapi/js/jsapi/egw_images.js b/phpgwapi/js/jsapi/egw_images.js
index 2c4fd4c167..544cd27f79 100644
--- a/phpgwapi/js/jsapi/egw_images.js
+++ b/phpgwapi/js/jsapi/egw_images.js
@@ -48,18 +48,20 @@ egw.extend('images', egw.MODULE_GLOBAL, function() {
 			// For logging all paths tried
 			var tries = {};
 
-			if (typeof _app == 'undefined')
+			if (typeof _app === 'undefined')
 			{
-				if(_name.indexOf('/') > 0)
+				// If the application name is not given, set it to the name of
+				// current application
+				_app = this.getAppName();
+
+				// If this.getAppName does not work, try to determine the image
+				// by looking at the image path.
+				if(!_app && _name.indexOf('/') > 0)
 				{
 					var split = et2_csvSplit(_value, 2,"/");
 					var _app = split[0];
 					_name = split[1];
 				}
-				else
-				{
-					_app = this.getAppName();
-				}
 			}
 			
 			// own instance specific images in vfs have highest precedence
diff --git a/phpgwapi/js/jsapi/egw_json.js b/phpgwapi/js/jsapi/egw_json.js
index f66f014fdf..e1bb5e3f43 100644
--- a/phpgwapi/js/jsapi/egw_json.js
+++ b/phpgwapi/js/jsapi/egw_json.js
@@ -21,7 +21,7 @@
 	egw_debug;
 */
 
-egw.extend('json', egw.MODULE_WND_LOCAL, function(_egw, _wnd) {
+egw.extend('json', egw.MODULE_WND_LOCAL, function(_app, _wnd) {
 
 	/**
 	 * Object which contains all registered handlers for JS responses.
diff --git a/phpgwapi/js/jsapi/egw_tooltip.js b/phpgwapi/js/jsapi/egw_tooltip.js
index a268494c15..0ff0e4093a 100644
--- a/phpgwapi/js/jsapi/egw_tooltip.js
+++ b/phpgwapi/js/jsapi/egw_tooltip.js
@@ -17,7 +17,7 @@
 	egw_core;
 */
 
-egw.extend('tooltip', egw.MODULE_WND_LOCAL, function(_egw, _wnd) {
+egw.extend('tooltip', egw.MODULE_WND_LOCAL, function(_app, _wnd) {
 
 	var tooltip_div = null;
 	var current_elem = null;