i have the black back ground on, the icons are white/grey. i have bold, italic, font size, more option, SPACE, list, alignment, paragraph format, SPACE, insert link, insert image, more options, then nothing all the way over to undo, more options and preview
Are you using a mobile device (if so you need to click on the more options to see the emoji, etc. items)? If not, please switch to the "Light Style" and posting a screen capture of the tool bar. I have tested Firefox, Chrome, Safari and Opera and no items are missing.