diff --git a/compiler/js/component.py b/compiler/js/component.py
index 48b0848d..ff732707 100644
--- a/compiler/js/component.py
+++ b/compiler/js/component.py
@@ -358,6 +358,16 @@ def generate_prototype(self, registry, ident_n = 1):
 						args.append(default_value)
 					r.append("%score.addProperty(%s)" %(ident, ", ".join(args)))
 
+		setup_on_changed = []
+
+		for target, value in self.assignments.items():
+			if target == "id" or target.endswith(".id"):
+				continue
+			else:
+				if "." not in target and lang.value_is_trivial(value):
+					r.append("%s$core._protoDefault(%s, '%s', %s)" %(ident, self.proto_name, target, value))
+					setup_on_changed.append("%s$core._setProtoDefault($this, '%s')" %(ident, target	))
+
 		for name, prop in self.enums.items():
 			values = prop.values
 
@@ -411,6 +421,7 @@ def put_in_prototype(handler):
 			for (path, name) in handlers:
 				assert not path
 				r.append("%s$core._protoOnChanged(%s, '%s', %s)" %(ident, self.proto_name, name, code))
+				setup_on_changed.append("%s$core._setProtoDefault($this, '%s')" %(ident, name))
 
 		for code, handlers in self.transform_handlers(registry, self.signal_handlers):
 			handlers = list(filter(put_in_prototype, handlers))
@@ -448,10 +459,10 @@ def put_in_prototype(handler):
 
 		setup_code = self.generate_setup_code(registry, '$this', '$c', ident_n + 2).strip()
 		b = '%s%s.$s.call($this, $c.$b); delete $c.$b' %(ident, self.base_proto_name)
-		if setup_code:
+		if setup_code or setup_on_changed:
 			generate = True
-		setup_code = '%s%s.$s = function($c) {\n\t\tvar $this = this;\n%s\n%s\n}' \
-			%(ident, self.proto_name, b, setup_code)
+		setup_code = '%s%s.$s = function($c) {\n\t\tvar $this = this;\n%s\n%s\n%s\n}' \
+			%(ident, self.proto_name, b, "\n".join(setup_on_changed), setup_code)
 
 		if generate:
 			r.append('')
@@ -640,6 +651,8 @@ def generate_setup_code(self, registry, parent, closure, ident_n = 1):
 		for target, value in self.assignments.items():
 			if target == "id":
 				continue
+			if self.prototype and "." not in target and lang.value_is_trivial(value):
+				continue
 			t = type(value)
 			#print self.name, target, value
 			target_owner, target_lvalue, target_prop = self.get_lvalue(registry, parent, target)
diff --git a/core/core.js b/core/core.js
index 8e2d6412..04c05d15 100644
--- a/core/core.js
+++ b/core/core.js
@@ -643,20 +643,27 @@ exports.addProperty = function(proto, type, name, defaultValue) {
 		defaultValue = getDefaultValueForType(type)
 	}
 
+	var protoDefault = '__default__' + name
+	var getDefaultValue = function(parent) {
+		if (protoDefault in parent)
+			return parent[protoDefault]
+		return defaultValue
+	}
+
 	var createStorage = function(newValue) {
 		var properties = this.__properties
 		var storage = properties[name]
 		if (storage === undefined) { //no storage
-			if (newValue === defaultValue) //value === defaultValue, no storage allocation
+			if (newValue === getDefaultValue(this)) //value === defaultValue, no storage allocation
 				return
-			storage = properties[name] = new PropertyStorage(defaultValue)
+			storage = properties[name] = new PropertyStorage(getDefaultValue(this))
 		}
 		return storage
 	}
 
 	var simpleGet = function() {
 		var storage = this.__properties[name]
-		return storage !== undefined? storage.getSimpleValue(defaultValue): defaultValue
+		return storage !== undefined? storage.getSimpleValue(getDefaultValue(this)): getDefaultValue(this)
 	}
 
 	var simpleSet = function(newValue) {
@@ -665,14 +672,14 @@ exports.addProperty = function(proto, type, name, defaultValue) {
 		if (storage === undefined)
 			return
 
-		storage.set(this, name, newValue, defaultValue, true)
+		storage.set(this, name, newValue, getDefaultValue(this), true)
 	}
 
 	var animatedGet = function() {
 		var storage = this.__properties[name]
 		return storage !== undefined?
-			storage.getCurrentValue(defaultValue):
-			defaultValue
+			storage.getCurrentValue(getDefaultValue(this)):
+			getDefaultValue(this)
 	}
 
 	var animatedSet = function(newValue) {
@@ -691,7 +698,7 @@ exports.addProperty = function(proto, type, name, defaultValue) {
 
 			storage.started = Date.now()
 
-			var src = storage.getCurrentValue(defaultValue)
+			var src = storage.getCurrentValue(getDefaultValue(this))
 			var dst = newValue
 
 			var self = this
@@ -721,7 +728,7 @@ exports.addProperty = function(proto, type, name, defaultValue) {
 					complete()
 				} else {
 					storage.interpolatedValue = convert(animation.interpolate(dst, src, t))
-					storage.callOnChanged(self, name, storage.getCurrentValue(defaultValue), src)
+					storage.callOnChanged(self, name, storage.getCurrentValue(getDefaultValue(this)), src)
 					storage.frameRequest = backend.requestAnimationFrame(nextFrame)
 				}
 			})
@@ -735,7 +742,7 @@ exports.addProperty = function(proto, type, name, defaultValue) {
 			animation.running = true
 			animation.complete = complete
 		}
-		storage.set(this, name, newValue, defaultValue, !animation)
+		storage.set(this, name, newValue, getDefaultValue(this), !animation)
 		// if ((!animation || !animation.running) && newValue === defaultValue)
 		// 	this.__properties[name] = undefined
 	}
@@ -831,6 +838,21 @@ $core._protoOnChanged = function(proto, name, callback)
 $core._protoOnKey = function(proto, name, callback)
 { protoEvent('__key__', proto, name, callback) }
 
+$core._protoDefault = function(proto, name, value)
+{ proto['__default__' + name] = value }
+
+$core._setProtoDefault = function(object, name) {
+	if (!('__properties' in object))
+		return
+
+	var value = object['__default__' + name]
+	if (value === undefined)
+		return
+
+	var storage = object.__properties[name]
+	_callOnChanged(object, name, value, storage? storage.onChanged: undefined)
+}
+
 $core.callMethod = function(obj, name) {
 	if (!obj)
 		return