Hi Dueldogg,
Thanks for opening this as a new post. So, trying to recreate your issue, I created a new project using Landscape Mountains feature pack and dragged a rock into scene, then a tree, and finally added a material from this pack to default BSP plane. All of these changes applied with no delay/freezing at all.
Please provide some more specific steps so that we can reproduce issue here in order to evaluate. For instance, am I using same assets you are? Are you creating a blank project and then adding assets? Please be as specific as possible.
Thanks again for your cooperation in troubleshooting this issue.