diff --git a/mithril.js b/mithril.js
index ee63e707..da004c57 100644
--- a/mithril.js
+++ b/mithril.js
@@ -328,10 +328,13 @@ var renderService = function($window) {
 		if (vnode.instance != null) {
 			var element = createNode(vnode.instance, hooks, ns)
 			vnode.dom = vnode.instance.dom
-			vnode.domSize = vnode.instance.domSize
+			vnode.domSize = vnode.dom != null ? vnode.instance.domSize : 0
 			return element
 		}
-		else return $emptyFragment
+		else {
+			vnode.domSize = 0
+			return $emptyFragment
+		}
 	}
 	//update
 	function updateNodes(parent, old, vnodes, hooks, nextSibling, ns) {
@@ -341,12 +344,12 @@ var renderService = function($window) {
 		else {
 			var recycling = isRecyclable(old, vnodes)
 			if (recycling) old = old.concat(old.pool)
-		
+			
 			var oldStart = 0, start = 0, oldEnd = old.length - 1, end = vnodes.length - 1, map
 			while (oldEnd >= oldStart && end >= start) {
 				var o = old[oldStart], v = vnodes[start]
 				if (o === v) oldStart++, start++
-				else if (o != null && v != null && o.key === v.key) {
+				else if (o != null && v != null && o.key === v.key && o.tag === v.tag) {
 					oldStart++, start++
 					updateNode(parent, o, v, hooks, getNextSibling(old, oldStart, nextSibling), recycling, ns)
 					if (recycling && o.tag === v.tag) insertNode(parent, toFragment(o), nextSibling)
@@ -354,7 +357,7 @@ var renderService = function($window) {
 				else {
 					var o = old[oldEnd]
 					if (o === v) oldEnd--, start++
-					else if (o != null && v != null && o.key === v.key) {
+					else if (o != null && v != null && o.key === v.key && o.tag === v.tag) {
 						updateNode(parent, o, v, hooks, getNextSibling(old, oldEnd + 1, nextSibling), recycling, ns)
 						insertNode(parent, toFragment(o), getNextSibling(old, oldStart, nextSibling))
 						oldEnd--, start++
@@ -365,10 +368,10 @@ var renderService = function($window) {
 			while (oldEnd >= oldStart && end >= start) {
 				var o = old[oldEnd], v = vnodes[end]
 				if (o === v) oldEnd--, end--
-				else if (o != null && v != null && o.key === v.key) {
+				else if (o != null && v != null && o.key === v.key && o.tag === v.tag) {
 					updateNode(parent, o, v, hooks, getNextSibling(old, oldEnd + 1, nextSibling), recycling, ns)
 					if (recycling && o.tag === v.tag) insertNode(parent, toFragment(o), nextSibling)
-					nextSibling = o.dom
+					if (o.dom != null) nextSibling = o.dom
 					oldEnd--, end--
 				}
 				else {
@@ -380,7 +383,7 @@ var renderService = function($window) {
 							updateNode(parent, movable, v, hooks, getNextSibling(old, oldEnd + 1, nextSibling), recycling, ns)
 							insertNode(parent, toFragment(movable), nextSibling)
 							old[oldIndex].skip = true
-							nextSibling = movable.dom
+							if (movable.dom != null) nextSibling = movable.dom
 						}
 						else {
 							var dom = createNode(v, hooks, undefined)
@@ -440,7 +443,7 @@ var renderService = function($window) {
 		if (children != null) {
 			for (var i = 0; i < children.length; i++) {
 				var child = children[i]
-				if (child != null) {
+				if (child != null && child.dom != null) {
 					if (vnode.dom == null) vnode.dom = child.dom
 					domSize += child.domSize || 1
 				}
@@ -479,7 +482,12 @@ var renderService = function($window) {
 		}
 		else if (old.instance != null) {
 			removeNode(parent, old.instance, null, false)
-			vnode.dom = vnode.domSize = undefined
+			vnode.dom = undefined
+			vnode.domSize = 0
+		}
+		else {
+			vnode.dom = old.dom
+			vnode.domSize = old.domSize
 		}
 	}
 	function isRecyclable(old, vnodes) {
@@ -506,7 +514,7 @@ var renderService = function($window) {
 	}
 	function toFragment(vnode) {
 		var count = vnode.domSize
-		if (count != null) {
+		if (count != null || vnode.dom == null) {
 			var fragment = $doc.createDocumentFragment()
 			if (count > 0) {
 				var dom = vnode.dom
@@ -519,7 +527,7 @@ var renderService = function($window) {
 	}
 	function getNextSibling(vnodes, i, nextSibling) {
 		for (; i < vnodes.length; i++) {
-			if (vnodes[i] != null) return vnodes[i].dom
+			if (vnodes[i] != null && vnodes[i].dom != null) return vnodes[i].dom
 		}
 		return nextSibling
 	}
@@ -699,12 +707,12 @@ var renderService = function($window) {
 	function copy(data) {
 		if (data instanceof Array) {
 			var output = []
-			for (var i = 0; i < data.length; i++) output[i] = copy(data[i])
+			for (var i = 0; i < data.length; i++) output[i] = data[i]
 			return output
 		}
 		else if (typeof data === "object") {
 			var output = {}
-			for (var i in data) output[i] = copy(data[i])
+			for (var i in data) output[i] = data[i]
 			return output
 		}
 		return data
diff --git a/render/render.js b/render/render.js
index 52abd954..62227b17 100644
--- a/render/render.js
+++ b/render/render.js
@@ -98,10 +98,13 @@ module.exports = function($window) {
 		if (vnode.instance != null) {
 			var element = createNode(vnode.instance, hooks, ns)
 			vnode.dom = vnode.instance.dom
-			vnode.domSize = vnode.instance.domSize
+			vnode.domSize = vnode.dom != null ? vnode.instance.domSize : 0
 			return element
 		}
-		else return $emptyFragment
+		else {
+			vnode.domSize = 0
+			return $emptyFragment
+		}
 	}
 
 	//update
@@ -112,12 +115,12 @@ module.exports = function($window) {
 		else {
 			var recycling = isRecyclable(old, vnodes)
 			if (recycling) old = old.concat(old.pool)
-		
+			
 			var oldStart = 0, start = 0, oldEnd = old.length - 1, end = vnodes.length - 1, map
 			while (oldEnd >= oldStart && end >= start) {
 				var o = old[oldStart], v = vnodes[start]
 				if (o === v) oldStart++, start++
-				else if (o != null && v != null && o.key === v.key) {
+				else if (o != null && v != null && o.key === v.key && o.tag === v.tag) {
 					oldStart++, start++
 					updateNode(parent, o, v, hooks, getNextSibling(old, oldStart, nextSibling), recycling, ns)
 					if (recycling && o.tag === v.tag) insertNode(parent, toFragment(o), nextSibling)
@@ -125,7 +128,7 @@ module.exports = function($window) {
 				else {
 					var o = old[oldEnd]
 					if (o === v) oldEnd--, start++
-					else if (o != null && v != null && o.key === v.key) {
+					else if (o != null && v != null && o.key === v.key && o.tag === v.tag) {
 						updateNode(parent, o, v, hooks, getNextSibling(old, oldEnd + 1, nextSibling), recycling, ns)
 						insertNode(parent, toFragment(o), getNextSibling(old, oldStart, nextSibling))
 						oldEnd--, start++
@@ -136,10 +139,10 @@ module.exports = function($window) {
 			while (oldEnd >= oldStart && end >= start) {
 				var o = old[oldEnd], v = vnodes[end]
 				if (o === v) oldEnd--, end--
-				else if (o != null && v != null && o.key === v.key) {
+				else if (o != null && v != null && o.key === v.key && o.tag === v.tag) {
 					updateNode(parent, o, v, hooks, getNextSibling(old, oldEnd + 1, nextSibling), recycling, ns)
 					if (recycling && o.tag === v.tag) insertNode(parent, toFragment(o), nextSibling)
-					nextSibling = o.dom
+					if (o.dom != null) nextSibling = o.dom
 					oldEnd--, end--
 				}
 				else {
@@ -151,7 +154,7 @@ module.exports = function($window) {
 							updateNode(parent, movable, v, hooks, getNextSibling(old, oldEnd + 1, nextSibling), recycling, ns)
 							insertNode(parent, toFragment(movable), nextSibling)
 							old[oldIndex].skip = true
-							nextSibling = movable.dom
+							if (movable.dom != null) nextSibling = movable.dom
 						}
 						else {
 							var dom = createNode(v, hooks, undefined)
@@ -211,7 +214,7 @@ module.exports = function($window) {
 		if (children != null) {
 			for (var i = 0; i < children.length; i++) {
 				var child = children[i]
-				if (child != null) {
+				if (child != null && child.dom != null) {
 					if (vnode.dom == null) vnode.dom = child.dom
 					domSize += child.domSize || 1
 				}
@@ -250,7 +253,12 @@ module.exports = function($window) {
 		}
 		else if (old.instance != null) {
 			removeNode(parent, old.instance, null, false)
-			vnode.dom = vnode.domSize = undefined
+			vnode.dom = undefined
+			vnode.domSize = 0
+		}
+		else {
+			vnode.dom = old.dom
+			vnode.domSize = old.domSize
 		}
 	}
 	function isRecyclable(old, vnodes) {
@@ -277,7 +285,7 @@ module.exports = function($window) {
 	}
 	function toFragment(vnode) {
 		var count = vnode.domSize
-		if (count != null) {
+		if (count != null || vnode.dom == null) {
 			var fragment = $doc.createDocumentFragment()
 			if (count > 0) {
 				var dom = vnode.dom
@@ -290,7 +298,7 @@ module.exports = function($window) {
 	}
 	function getNextSibling(vnodes, i, nextSibling) {
 		for (; i < vnodes.length; i++) {
-			if (vnodes[i] != null) return vnodes[i].dom
+			if (vnodes[i] != null && vnodes[i].dom != null) return vnodes[i].dom
 		}
 		return nextSibling
 	}
@@ -479,12 +487,12 @@ module.exports = function($window) {
 	function copy(data) {
 		if (data instanceof Array) {
 			var output = []
-			for (var i = 0; i < data.length; i++) output[i] = copy(data[i])
+			for (var i = 0; i < data.length; i++) output[i] = data[i]
 			return output
 		}
 		else if (typeof data === "object") {
 			var output = {}
-			for (var i in data) output[i] = copy(data[i])
+			for (var i in data) output[i] = data[i]
 			return output
 		}
 		return data
diff --git a/render/tests/test-component.js b/render/tests/test-component.js
index 828585c7..c6078469 100644
--- a/render/tests/test-component.js
+++ b/render/tests/test-component.js
@@ -640,10 +640,11 @@ o.spec("component", function() {
 		})
 	})
 	o.spec("state", function() {
-		o("deep copies state", function() {
+		o("copies state", function() {
 			var called = 0
+			var data = {a: 1}
 			var component = {
-				data: [{a: 1}],
+				data: data,
 				oninit: init,
 				view: function() {
 					return ""
@@ -653,7 +654,27 @@ o.spec("component", function() {
 			render(root, [{tag: component}])
 
 			function init(vnode) {
-				o(vnode.state.data).deepEquals([{a: 1}])
+				o(vnode.state.data).deepEquals(data)
+				o(vnode.state.data).equals(data)
+			}
+		})
+		o("state copy is shallow", function() {
+			var called = 0
+			var body = {a: 1}
+			var data = [body]
+			var component = {
+				data: data,
+				oninit: init,
+				view: function() {
+					return ""
+				}
+			}
+
+			render(root, [{tag: component}])
+
+			function init(vnode) {
+				o(vnode.state.data).equals(data)
+				o(vnode.state.data[0]).equals(body)
 			}
 		})
 	})
diff --git a/render/tests/test-updateNodes.js b/render/tests/test-updateNodes.js
index 29ea9fe9..598f0910 100644
--- a/render/tests/test-updateNodes.js
+++ b/render/tests/test-updateNodes.js
@@ -813,4 +813,36 @@ o.spec("updateNodes", function() {
 		o(root.childNodes[0].nodeName).equals("A")
 		o(root.childNodes[1].nodeName).equals("B")
 	})
+	o("fragment child toggles from null when followed by null component then tag", function() {
+		var component = {view: function() {return null}}
+		var vnodes = [{tag: "[", children: [{tag: "a"}, {tag: component}, {tag: "b"}]}]
+		var temp = [{tag: "[", children: [null, {tag: component}, {tag: "b"}]}]
+		var updated = [{tag: "[", children: [{tag: "a"}, {tag: component}, {tag: "b"}]}]
+
+		render(root, vnodes)
+		render(root, temp)
+		render(root, updated)
+
+		o(root.childNodes.length).equals(2)
+		o(root.childNodes[0].nodeName).equals("A")
+		o(root.childNodes[1].nodeName).equals("B")
+	})
+	o("fragment child toggles from null in component when followed by null component then tag", function() {
+		var flag = true
+		var a = {view: function() {return flag ? {tag: "a"} : null}}
+		var b = {view: function() {return null}}
+		var vnodes = [{tag: "[", children: [{tag: a}, {tag: b}, {tag: "s"}]}]
+		var temp = [{tag: "[", children: [{tag: a}, {tag: b}, {tag: "s"}]}]
+		var updated = [{tag: "[", children: [{tag: a}, {tag: b}, {tag: "s"}]}]
+
+		render(root, vnodes)
+		flag = false
+		render(root, temp)
+		flag = true
+		render(root, updated)
+
+		o(root.childNodes.length).equals(2)
+		o(root.childNodes[0].nodeName).equals("A")
+		o(root.childNodes[1].nodeName).equals("S")
+	})
 })