diff --git a/ui (gen4)/data.js b/ui (gen4)/data.js
index 42b7ece2..9a0417ec 100755
--- a/ui (gen4)/data.js	
+++ b/ui (gen4)/data.js	
@@ -1815,16 +1815,205 @@ var DataPrototype = {
 
 
 
+/*********************************************************************/
+
+var DataWithTagsPrototype = {
+
+	// XXX need a unified init/dump/load scheme...
+	loadJSON: function(json){
+		json = typeof(json) == typeof('str') ? JSON.parse(json) : json
+
+		// XXX hate manual super calls...
+		DataWithTagsPrototype.__proto__.loadJSON.call(this, json)
+
+		if(json.tags != null){
+			// XXX should we make  copy here???
+			this.tags = json.tags
+			this.sortTags()
+		}
+		
+		return this
+	},
+	dumpJSON: function(){
+		// XXX hate manual super calls...
+		var res = DataWithTagsPrototype.__proto__.dumpJSON.call(this)
+
+		if(this.tags != null){
+			var tags = this.tags
+			res.tags = {}
+			Object.keys(tags).forEach(function(tag){
+				res.tags[tag] = tags[tag].compact()
+			})
+		}
+
+		return res
+	},
+
+	sortTags: function(){
+		var that = this
+		var tags = this.tags
+
+		if(tags == null){
+			return this
+		}
+
+		Object.keys(tags).forEach(function(tag){
+			tags[tag] = that.makeSparseImages(tags[tag])
+		})
+		return this
+	},
+
+	tag: function(tags, gids){
+		tags = tags.constructor !== Array ? [tags] : tags
+
+		gids = gids == null ? this.getImage() : gids
+		gids = gids.constructor !== Array ? [gids] : gids
+
+		if(this.tags == null){
+			this.tags = {}
+		}
+
+		var that = this
+		var tagset = this.tags
+		var order = this.order
+		tags.forEach(function(tag){
+			gids.forEach(function(gid){
+				if(tagset[tag] == null){
+					tagset[tag] = []
+				}
+				tagset[tag][order.indexOf(gid)] = gid
+			})
+		})
+
+		return this
+	},
+	untag: function(tags, gids){
+		tags = tags.constructor !== Array ? [tags] : tags
+
+		gids = gids == null ? this.getImage() : gids
+		gids = gids.constructor !== Array ? [gids] : gids
+
+		var that = this
+		var tagset = this.tags
+		var order = this.order
+		tags.forEach(function(tag){
+			gids.forEach(function(gid){
+				delete tagset[tag][order.indexOf(gid)]
+			})
+			if(tagset[tag].length == 0){
+				delete tagset[tag]
+			}
+		})
+
+		return this
+	},
+
+	getTags: function(gids){
+		gids = gids == null ? this.getImage() : gids
+		gids = gids.constructor !== Array ? [gids] : gids
+
+		if(this.tags == null){
+			return []
+		}
+
+		var tags = this.tags
+		var order = this.order
+
+		// index the gids...
+		var indexes = gids.map(function(gid){ return order.indexOf(gid) })
+
+		// return only those tags that have at least one non-null gid index...
+		return Object.keys(tags).filter(function(tag){
+			return indexes.filter(function(i){ 
+				return tags[tag][i] != null 
+			}).length > 0
+		})
+	},
+
+	// selectors...
+	getTaggedByAny: function(tags){
+		tags = tags.constructor !== Array ? [tags] : tags
+
+		var res = []
+
+		if(this.tags == null){
+			return res
+		}
+
+		var that = this
+		var tagset = this.tags
+		tags.forEach(function(tag){
+			if(tag in tagset){
+				that.makeSparseImages(tagset[tag], res)
+			}
+		})
+
+		return res.compact()
+	},
+	getTaggedByAll: function(tags){
+		tags = tags.constructor !== Array ? [tags] : tags
+
+		if(this.tags == null){
+			return []
+		}
+
+		var index = []
+		var l = tags.length
+
+		// count how many of the tags each image is tagged...
+		var that = this
+		var tagset = this.tags
+		tags.forEach(function(tag){
+			if(tag in tagset){
+				Object.keys(tagset[tag]).forEach(function(n){
+					if(index[n] == null){
+						index[n] = 1
+					} else {
+						index[n] += 1
+					}
+				})
+			}
+		})
+
+		// filter only the images tagged by all of the tags...
+		var order = this.order
+		var res = []
+		var i = index.indexOf(l)
+		while(i != -1){
+			res.push(order[i])
+			delete index[i]
+
+			i = index.indexOf(l)
+		}
+
+		return res
+	},
+}
+DataWithTagsPrototype.__proto__ = DataPrototype
+
+
+
 /*********************************************************************/
 
 // Main Data object...
-var Data = 
-module.Data = 
-object.makeConstructor('Data', 
+var BaseData = 
+module.BaseData = 
+object.makeConstructor('BaseData', 
 		DataClassPrototype, 
 		DataPrototype)
 
 
+var DataWithTags = 
+module.DataWithTags = 
+object.makeConstructor('DataWithTags', 
+		DataClassPrototype, 
+		DataWithTagsPrototype)
+
+
+var Data =
+module.Data = DataWithTags
+
+
 
 /**********************************************************************
 * vim:set ts=4 sw=4 :                                                */
diff --git a/ui (gen4)/lib/jli.js b/ui (gen4)/lib/jli.js
index 9cbce79d..35e14d25 100755
--- a/ui (gen4)/lib/jli.js	
+++ b/ui (gen4)/lib/jli.js	
@@ -1338,7 +1338,8 @@ Array.prototype.compact = function(){
 // like .length but for sparse arrays will return the element count...
 // XXX make this a prop...
 Array.prototype.len = function(){
-	return this.compact().length
+	//return this.compact().length
+	return Object.keys(this).length
 }
 
 
diff --git a/ui (gen4)/tags.js b/ui (gen4)/tags.js
deleted file mode 100755
index 92fc85d4..00000000
--- a/ui (gen4)/tags.js	
+++ /dev/null
@@ -1,44 +0,0 @@
-/**********************************************************************
-* 
-*
-*
-**********************************************************************/
-
-define(function(require){ var module = {}
-console.log('>>> tags')
-
-//var DEBUG = DEBUG != null ? DEBUG : true
-
-var object = require('object')
-
-
-
-/*********************************************************************/
-
-var TagsClassPrototype = {}
-
-
-var TagsPrototype = {
-	loadJSON: function(json){
-	},
-	dumpJSON: function(){
-	},
-
-	_reset: function(){
-	},
-}
-
-
-/*********************************************************************/
-
-var Tags =
-module.Tags = 
-object.makeConstructor('Tags', 
-		TagsClassPrototype, 
-		TagsPrototype)
-
-
-
-/**********************************************************************
-* vim:set ts=4 sw=4 :                                                */
-return module })