diff --git a/readme.txt b/readme.txt
index 904978a..734f19c 100644
--- a/readme.txt
+++ b/readme.txt
@@ -75,6 +75,7 @@ You can report security bugs through the Patchstack Vulnerability Disclosure Pro
 == Changelog ==
 
 = 1.4.1 =
+* We added an indeterminate visual display of the "All" checkbox, e.g. while selecting posts.
 * We fixed displaying post type visibility settings inside the site editor.
 
 = 1.4.0 =
diff --git a/src/control/controls.js b/src/control/controls.js
index 2ae3ff1..63841c0 100644
--- a/src/control/controls.js
+++ b/src/control/controls.js
@@ -632,6 +632,19 @@ const addControls = createHigherOrderComponent( ( BlockEdit ) => {
 														  ]
 														: false
 												}
+												indeterminate={
+													hidePosts &&
+													hidePosts[ type ] &&
+													! hidePosts[ type ][
+														'all'
+													] &&
+													Object.values(
+														hidePosts[ type ]
+													).some(
+														( item ) =>
+															item === true
+													)
+												}
 												value="all"
 												onChange={ ( value ) =>
 													onChangePostsAll(