Speech bubbles on the front cover

I am learning to use the new Comic Tool in Bloom 4.7.104. I assumed that I would be able to add speech bubbles to the front cover illustration, but the tool is greyed out when the front cover is selected. Am I missing something? Or does the tool really not function for the front cover?

Sorry, it really does not function for the front cover.

Thanks, John–I just wanted to make sure. Might be worth adding to the release notes.