option to replace the section when you drag it on of an existing section

I normally sitemap the website first and then I go 'wireframe' it. Once I add a pre-made section a new section can be seen in the sitemap with the name of that section. There is no updating between sitemap and wireframe. So when I drag in a section, it will not fit in the section I already made in the sitemap. So I end up with the sitemapped section + the new one. I have to rename and delete and I hate doing things twice ;)