More logging.
Only reselect the gallery if it has the same ID as the previously selected one.
Always focus the editor if the mousedown is on a gallery block.
When removing a gallery, reset the selected state.
If a gallery block is selected and the user hits delete or backspace, remove the gallery.
Replace the parent node in addition to the gallery block if it is a paragraph, rename the id used on the root node of a gallery block, and adjust the attributes of the image placeholder element.
Actually include a src for the transparent image placeholder.