Custom Pipeline Components Not Updating

I’m sure many BizTalk developers who create custom pipeline components will have run into this problem. You create a custom pipeline component, deploy it, and something doesn’t quite work. Back into Visual Studio and make some code fixes, looks good and redeploy. Test your fix only to find your changes don’t appear to have come across. Ok, rebuild everything and try again. Still no joy? You then start ripping out your solution, removing assemblies from the GAC, restarting Visual Studio etc. until it eventually seems to deploy, but you have no idea which step it was that solved the issue.  

The answer to the problem is Visual Studio is trying to be to helpful. When you add your custom pipeline components into the toolbox on the pipeline editor Visual Studio caches that version. Therefore simply restarting Visual Studio will not work no matter how many times you remove the old assemblies from the GAC. You need to remove the custom pipeline component from the toolbar. Restart Visual Studio and add the component back into the toolbar. Alas the component has been updated.