First off: I am fairly new to Sitefinity and most of my experience is in a LAMP environment so I can't really dig into this as much as I'd like to be able to.
Sometimes when our user(s) are editing pages some blocks that are inserted then cannot be deleted without scrapping the entire page and starting over. Sometimes choosing "Delete" actually causes the browser to scroll non-stop to the top of the DOM of the editor until you refresh the page, in which case the block is still not deleted.
Any words of advice?Also, I am curious if anyone things that updating Sitefinity would fix this issue. I am new to this job but it looks like they have been running version 9.0 so they are about 3 major releases behind now.
I would suggest submitting a support ticket for further investigation. This does not seem like a common Sitefinity issues based on my years working with the product.