diff --git a/css/reveal.scss b/css/reveal.scss
index 022793af..df039788 100644
--- a/css/reveal.scss
+++ b/css/reveal.scss
@@ -1073,7 +1073,7 @@ $controlsArrowAngleActive: 36deg;
 	background: black;
 	visibility: hidden;
 	opacity: 0;
-	z-index: 100;
+	z-index: 10001;
 	transition: all 1s ease;
 }
 
diff --git a/js/controllers/keyboard.js b/js/controllers/keyboard.js
index 191e1b91..f09cd938 100644
--- a/js/controllers/keyboard.js
+++ b/js/controllers/keyboard.js
@@ -190,7 +190,7 @@ export default class Keyboard {
 			}
 		}
 
-		if( this.Reveal.isOverlayOpen() && !['Escape', 'f', 'c'].includes(event.key) ) {
+		if( this.Reveal.isOverlayOpen() && !["Escape", "f", "c", "b", "."].includes(event.key) ) {
 			return false;
 		}