diff --git a/web/presentation_mode.js b/web/presentation_mode.js
index 5d72e7c43..0c3253b34 100644
--- a/web/presentation_mode.js
+++ b/web/presentation_mode.js
@@ -150,6 +150,11 @@ var PresentationMode = {
     HandTool.enterPresentationMode();
     this.contextMenuOpen = false;
     this.container.setAttribute('contextmenu', 'viewerContextMenu');
+
+    // Text selection is disabled in Presentation Mode, thus it's not possible
+    // for the user to deselect text that is selected (e.g. with "Select all")
+    // when entering Presentation Mode, hence we remove any active selection.
+    window.getSelection().removeAllRanges();
   },
 
   exit: function presentationModeExit() {
diff --git a/web/viewer.css b/web/viewer.css
index 856a0c881..4fbe0845b 100644
--- a/web/viewer.css
+++ b/web/viewer.css
@@ -55,6 +55,7 @@ select {
   height: 100%;
   overflow: hidden;
   cursor: none;
+  -webkit-user-select: none;
 }
 
 #viewerContainer:-moz-full-screen {
@@ -65,6 +66,7 @@ select {
   height: 100%;
   overflow: hidden;
   cursor: none;
+  -moz-user-select: none;
 }
 
 #viewerContainer:-ms-fullscreen {
@@ -74,6 +76,7 @@ select {
   height: 100%;
   overflow: hidden !important;
   cursor: none;
+  -ms-user-select: none;
 }
 
 #viewerContainer:-ms-fullscreen::-ms-backdrop {
@@ -88,6 +91,9 @@ select {
   height: 100%;
   overflow: hidden;
   cursor: none;
+  -webkit-user-select: none;
+  -moz-user-select: none;
+  -ms-user-select: none;
 }
 
 :-webkit-full-screen a:not(.internalLink) {