Hi,

Thanks for this code guys, just what I needed and works fine in I.E. However in Firefox the disabled tabs don't change appearance, I made this minor mod to fix this:

I added the folowing lines to set_enabled to add and remove the ajax_tab_disabled class from the header::

set_enabled : function(value) {
        if (value != this._enabled) {
            this._enabled = value;
            if (value)
				Sys.UI.DomElement.removeCssClass(this._header, "ajax__tab_disabled");
            else
				Sys.UI.DomElement.addCssClass(this._header, "ajax__tab_disabled");
				

            if (this.get_isInitialized()) {
                if (!this._enabled) {
                    this._hide();
                } else {
                    this._show();
                }
            }
            this.raisePropertyChanged("enabled");
        }
    }

Then I added the CSS class to the tabs.css:

.ajax__tab_xp .ajax__tab_disabled { color: Gray; }