diff --git a/package.json b/package.json
index c1efd81f..4ce35fbc 100644
--- a/package.json
+++ b/package.json
@@ -57,7 +57,7 @@
   "dependencies": {
     "@atlaskit/icon": "21.1.0",
     "@atlaskit/media-core": "32.2.0",
-    "@material-ui/core": "4.12.3",
+    "@material-ui/core": "4.11.4",
     "@material-ui/styles": "4.11.4",
     "classnames": "2.3.1",
     "cozy-bar": "7.16.0",
diff --git a/src/components/notes/EditorCorner.jsx b/src/components/notes/EditorCorner.jsx
index 15e7c209..b579f14a 100644
--- a/src/components/notes/EditorCorner.jsx
+++ b/src/components/notes/EditorCorner.jsx
@@ -7,13 +7,22 @@ import { useI18n } from 'cozy-ui/transpiled/react/I18n'
 
 import SharingWidget from 'components/notes/sharing'
 
+// https://mui.com/components/tooltips/#custom-child-element
+const ForwardedIcon = React.forwardRef(function ForwardedIcon(props, ref) {
+  return (
+    <div ref={ref}>
+      <Icon {...props} />
+    </div>
+  )
+})
+
 const EditorCorner = ({ doc, isPublic, isReadOnly, title }) => {
   const { t } = useI18n()
   if (!isPublic) return <SharingWidget file={doc.file} title={title} />
   else if (isReadOnly) {
     return (
       <Tooltip title={t('Notes.Editor.read_only')}>
-        <Icon icon="lock" color="var(--primaryTextColor)" />
+        <ForwardedIcon icon="lock" color="var(--primaryTextColor)" />
       </Tooltip>
     )
   } else return null
diff --git a/src/components/notes/editor.jsx b/src/components/notes/editor.jsx
index 19a37549..39811263 100644
--- a/src/components/notes/editor.jsx
+++ b/src/components/notes/editor.jsx
@@ -109,11 +109,13 @@ export default function Editor(props) {
           headerMenu={
             <HeaderMenu
               backFromEditing={
-                <BackFromEditing
-                  returnUrl={returnUrl}
-                  file={doc.file}
-                  requestToLeave={requestToLeave}
-                />
+                returnUrl ? (
+                  <BackFromEditing
+                    returnUrl={returnUrl}
+                    file={doc.file}
+                    requestToLeave={requestToLeave}
+                  />
+                ) : null
               }
               editorCorner={
                 <EditorCorner
@@ -151,5 +153,5 @@ Editor.propTypes = {
   noteId: PropTypes.string.isRequired,
   readOnly: PropTypes.bool.isRequired,
   userName: PropTypes.string,
-  returnUrl: PropTypes.string
+  returnUrl: PropTypes.oneOfType([PropTypes.string, PropTypes.bool]).isRequired
 }
diff --git a/src/targets/browser/index.jsx b/src/targets/browser/index.jsx
index 676ea025..af4d9bff 100644
--- a/src/targets/browser/index.jsx
+++ b/src/targets/browser/index.jsx
@@ -110,7 +110,7 @@ export const initApp = () => {
 
   const shareCode = getPublicSharecode()
   const token = shareCode || data.token
-  const isPublic = shareCode || !token || token == ''
+  const isPublic = Boolean(shareCode || !token || token == '')
 
   // initialize the client to interact with the cozy stack
   const client = new CozyClient({
diff --git a/yarn.lock b/yarn.lock
index 1b15f5b8..4878527c 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -3098,14 +3098,14 @@
     "@kenjiuno/decompressrtf" "^0.1.3"
     "@kenjiuno/iconvlite-wrapper-with-iso2022jp" "^0.1.0"
 
-"@material-ui/core@4.12.3":
-  version "4.12.3"
-  resolved "https://registry.yarnpkg.com/@material-ui/core/-/core-4.12.3.tgz#80d665caf0f1f034e52355c5450c0e38b099d3ca"
-  integrity sha512-sdpgI/PL56QVsEJldwEe4FFaFTLUqN+rd7sSZiRCdx2E/C7z5yK0y/khAWVBH24tXwto7I1hCzNWfJGZIYJKnw==
+"@material-ui/core@4.11.4":
+  version "4.11.4"
+  resolved "https://registry.yarnpkg.com/@material-ui/core/-/core-4.11.4.tgz#4fb9fe5dec5dcf780b687e3a40cff78b2b9640a4"
+  integrity sha512-oqb+lJ2Dl9HXI9orc6/aN8ZIAMkeThufA5iZELf2LQeBn2NtjVilF5D2w7e9RpntAzDb4jK5DsVhkfOvFY/8fg==
   dependencies:
     "@babel/runtime" "^7.4.4"
     "@material-ui/styles" "^4.11.4"
-    "@material-ui/system" "^4.12.1"
+    "@material-ui/system" "^4.11.3"
     "@material-ui/types" "5.1.0"
     "@material-ui/utils" "^4.11.2"
     "@types/react-transition-group" "^4.2.0"
@@ -3138,7 +3138,7 @@
     jss-plugin-vendor-prefixer "^10.5.1"
     prop-types "^15.7.2"
 
-"@material-ui/system@^4.12.1":
+"@material-ui/system@^4.11.3":
   version "4.12.1"
   resolved "https://registry.yarnpkg.com/@material-ui/system/-/system-4.12.1.tgz#2dd96c243f8c0a331b2bb6d46efd7771a399707c"
   integrity sha512-lUdzs4q9kEXZGhbN7BptyiS1rLNHe6kG9o8Y307HCvF4sQxbCgpL2qi+gUk+yI8a2DNk48gISEQxoxpgph0xIw==