I just spent way too much time working on this same issue, and it turned out to be an issue with the formatting of the web page that displayed the 1099-B sales entries. On the second page of entries, I could see the edit (pencil) icon, and trash icons, but on the first page they were not visible due to some poor formatting, and I therefore believed that editing was not possible. Very confusing.
In Chrome, I was able to solve the issue simply by changing the zoom on my browser far enough that the icons became visible when scrolling around on the screen (View --> Zoom In). This allowed me to hit the trash icon and remove the offending entries.
