Drag and Drop is not working for Upfront

I have tried two themes, Spirit and Luke and Sara, as starter themes for website redevelopment. I have tried adding regions and using drag and drop to add widgets, text, images, etc. and have found that I can add regions, but I cannot drag and drop anything. Rather it will add element in left region only (does not drag all the way across) and will highlight the entire site, which cannot be undone, causing me to reload the entire page and start over.

Any ideas on what is causing this and how to fix it?