ToolkitScriptManager Removed in v15.1
Starting with the v15.1 release, we have removed the ToolScriptManager due to various issues it caused. Use the standard ScriptManager.
Previous versions of ASP.NET AJAX Control Toolkit required that ToolkitScriptManager was used on each page with extenders. This control has been introduced back in 2007 to add features missing from the standard ScriptManager: script combining and CDN support.
Since then, ASP.NET has evolved, and ScriptManager can currently handle both tasks on its own with the help of the ASP.NET Web Optimization framework (check
ASP.NET 4.5 ScriptManager Improvements in WebForms
Another common issue is that Visual Studio ASP.NET templates contain ScriptManager on the master page by default. So using the ASP.NET AJAX Control Toolkit became complicated and required additional edits of the template to work with the ToolScriptManager.
Our top priority was to ensure that the ASP.NET AJAX Control Toolkit works with modern versions of Visual Studio and .NET. And that it also integrates seamlessly into the standard (modern) web templates.
In this v15.1 release, we have extensively reworked most of the code related to scripts, styles and images, and decided to leverage modern technologies available in the current .NET frameworks.
Script and CSS bundling is delegated to Bundles. This topic is covered in the following article: ”How
to use bundling and CDN