Index: ui.slider.js
===================================================================
--- ui.slider.js	(revision 3786)
+++ ui.slider.js	(working copy)
@@ -79,18 +79,18 @@
 		o = o || {};
 		$.extend(options, o);
 		$.extend(options, {
-			axis: o.axis || (el.offsetWidth < el.offsetHeight ? 'vertical' : 'horizontal'),
 			maxValue: parseInt(o.maxValue) || 100,
 			minValue: parseInt(o.minValue) || 0,
 			startValue: parseInt(o.startValue) || 0,
 			_start: function(h, p, c, t, e) {
+				calcDimensions(t.options);
 				self.start.apply(t, [self, e]); // Trigger the start callback				
 			},
 			_beforeStop: function(h, p, c, t, e) {
-				self.stop.apply(t, [self, e]); // Trigger the start callback
+				self.stop.apply(t, [self, e]); // Trigger the stop callback
 			},
 			_drag: function(h, p, c, t, e) {
-				self.drag.apply(t, [self, e]); // Trigger the start callback
+				self.drag.apply(t, [self, e, p]); // Trigger the drag callback
 			},
 			startCondition: function() {
 				return !self.disabled;
@@ -103,7 +103,20 @@
 		o.stepping = parseInt(o.stepping) || (o.steps ? o.maxValue/o.steps : 0);
 		o.realValue = (o.maxValue - o.minValue);
 
+		function calcDimensions(opt) {
+			opt.axis = options.axis || (el.offsetWidth < el.offsetHeight ? 'vertical' : 'horizontal');
+			if(opt.axis == 'horizontal') {
+				self.parentSize = $(self.element).outerWidth() - self.handle.outerWidth();
+				self.prop = 'left';
+			}
+			
+			if(opt.axis == 'vertical') {
+				self.parentSize = $(self.element).outerHeight() - self.handle.outerHeight();
+				self.prop = 'top';
+			}
+		}
 
+
 		this.handle = options.handle ? $(options.handle, el) : $('.ui-slider-handle', el);
 		if(this.handle.length == 1) {
 			this.interaction = new $.ui.mouseInteraction(this.handle[0], options);
@@ -119,17 +132,8 @@
 		this.element = el;
 		$(this.element).addClass("ui-slider");
 		
+		calcDimensions(o);
 		
-		if(o.axis == 'horizontal') {
-			this.parentSize = $(this.element).outerWidth() - this.handle.outerWidth();
-			this.prop = 'left';
-		}
-		
-		if(o.axis == 'vertical') {
-			this.parentSize = $(this.element).outerHeight() - this.handle.outerHeight();
-			this.prop = 'top';
-		}
-		
 		if(!this.multipleHandles) {
 			$(el).bind('click', function(e) { self.click.apply(self, [e]); });
 			if(!isNaN(o.startValue)) this.moveTo(o.startValue,options.realValue, null, false);
@@ -258,7 +262,6 @@
 			if(this.multipleHandles) return false; //TODO: Multiple handle moveTo function
 			
 			var o = this.interaction.options;
-			var offset = $(this.interaction.element).offsetParent().offset({ border: false });
 			this.interaction.pickValue = this.interaction.curValue;
 			value = value-o.minValue;