How do I clear the "Open Blocks" list in the Insert Block function?

When you select Insert Block it gives you a list of "Blocks to Insert" and has all the "Open Blocks" listed... how do I clear this list?

Sometimes this list is super long and the name of the "open block" will interfere with naming a feature or sketch.

Even when the block is deleted/exploded in the file the name remains on this list.

So how do I erase or clear the "Open Blocks" list in the Insert Block function?