This is the third time this has happened. The last few times I logged out and back in and reloaded the campaign and that seemed to reset something.
This time, no go. I'm editing a copied campaign if that makes any difference.
Why is this happeneing frequently now?
WIN7 Pro/Chrome 47.0.2526.111 m
Can you tell me what happens when you try to delete the different blocks? Do you get a pop up message asking if you are sure you want to delete the block, an error message, or something else?
Would you be able to try optimizing Chrome, then restarting your browser to see if this helps? If not, an Incognito window may help as well. Let us know if either of these work so that we can then troubleshoot further to determine the cause if needed.