Source: https://www.peeayecreative.com/how-to-make-the-text-style-options-sticky-within-the-divi-builder-module-text-areas/

When you edit text in one of Divi’s text areas, you have to keep scrolling up and down to the TinyMCE menu to make a word bold or add a link or make a blockquote.

This CSS makes the Tiny MCE meu stick at the top of the text area

/* START Sticky visual text styling menubar in Divi Builder */
.mce-panel .mce-stack-layout-item.mce-first {
position: sticky!important;
top: -60px;
}
/* END Sticky visual text styling menubar in Divi Builder */
Code language: CSS (css)