diff --git a/res/css/views/dialogs/_CompoundDialog.pcss b/res/css/views/dialogs/_CompoundDialog.pcss
index dc0e61b65e..15df4f3951 100644
--- a/res/css/views/dialogs/_CompoundDialog.pcss
+++ b/res/css/views/dialogs/_CompoundDialog.pcss
@@ -88,6 +88,6 @@ limitations under the License.
 
     .mx_CompoundDialog_footer {
         box-shadow: 0px -4px 4px rgba(0, 0, 0, 0.05); /* hardcoded colour for both themes */
-        z-index: 1;
+        z-index: 1; /* needed to make footer & shadow appear above dialog content */
     }
 }