Hello alexprobb,
Gridblocks are added in Sections. The section menu is the small gray handle. Click on the right side (the modification menu) and you will see a Delete option. Click that and the entire GridBlock section will be removed. All drag handles (Red – element, Blue – column, Yellow – row,and Gray – Gridblock) have a Delete option for their specific item. This way you can just remove the exact content you want and leave the rest.
Kindest Regards,
Scott M