diff --git a/packages/rich-text/src/to-tree.js b/packages/rich-text/src/to-tree.js
index 131174460a74bc..46671c951bc09d 100644
--- a/packages/rich-text/src/to-tree.js
+++ b/packages/rich-text/src/to-tree.js
@@ -299,6 +299,8 @@ export function toTree( {
 		if ( shouldInsertPadding && i === text.length ) {
 			append( getParent( pointer ), ZWNBSP );
 
+			// We CANNOT use CSS to add a placeholder with pseudo elements on
+			// the main block wrappers because that could clash with theme CSS.
 			if ( placeholder && text.length === 0 ) {
 				append( getParent( pointer ), {
 					type: 'span',