diff --git a/sudoku.js b/app.js
similarity index 72%
rename from sudoku.js
rename to app.js
index 706f45b..0889084 100644
--- a/sudoku.js
+++ b/app.js
@@ -19,6 +19,7 @@ window.onload = function() {
             if (!box.disabled) {
                 box.onfocus = onfocus
                 box.oninput = oninput
+                box.oncontextmenu = oncontextmenu
             }
             box.rowId = rowId
             box.columnId = columnId
@@ -37,16 +38,18 @@ window.onload = function() {
         box.neighbourhood = Array.from(box.neighbourhood)
     })
     boxes.forEach(searchCandidatesOf)
-    boxes.forEach(showCandidatesOn)
     enableButtons()
     highlightAndTab()
     
     if (/Win/.test(navigator.platform) || /Linux/.test(navigator.platform)) accessKeyModifiers = "Alt+Maj+"
     else if (/Mac/.test(navigator.platform)) accessKeyModifiers = "⌃⌥ "
     for(node of document.querySelectorAll("*[accesskey]")) {
-        node.title += " [" + (node.accessKeyLabel || accessKeyModifiers + "+" + node.accessKey) + "]"
+        node.title += " [" + (node.accessKeyLabel || accessKeyModifiers + node.accessKey) + "]"
     }
     
+    document.body.onclick = function (event) {
+        contextMenu.style.display = "none"
+    }
     suggestionTimer = setTimeout(showSuggestion, 30000)
 }
 
@@ -55,20 +58,6 @@ function searchCandidatesOf(box) {
     box.neighbourhood.forEach(neighbour => box.candidates.delete(neighbour.value))
 }
 
-function showCandidatesOn(box) {
-    if (!box.disabled) {
-        while (box.list.firstChild) box.list.firstChild.remove()
-        if (!box.value && box.candidates.size) {
-            const candidatesArray = Array.from(box.candidates).sort()
-            candidatesArray.forEach(candidate => {
-                option = document.createElement('option')
-                option.value = candidate
-                box.list.appendChild(option)
-            })
-        }
-    }
-}
-
 function onfocus() {
     this.previousValue = this.value
     this.select()
@@ -94,31 +83,30 @@ function refresh(box) {
 
     box.neighbourhood.concat([box]).forEach(neighbour => {
         searchCandidatesOf(neighbour)
-        showCandidatesOn(neighbour)
         neighbour.setCustomValidity("")
+        neighbour.required = false
     })
     
     enableButtons()
     highlightAndTab()
     
     for (neighbour1 of box.neighbourhood) {
-        neighbour1.setCustomValidity("")
         if (neighbour1.value.length) {
-            if (neighbour1.value) {
-                for (area of [
-                    {name: "région", neighbours: regions[neighbour1.regionId]},
-                    {name: "ligne", neighbours: rows[neighbour1.rowId]},
-                    {name: "colonne", neighbours: columns[neighbour1.columnId]},
-                ])
-                    for (neighbour2 of area.neighbours)
-                        if (neighbour2 != neighbour1 && neighbour2.value == neighbour1.value) {
-                            for (neighbour of [neighbour1, neighbour2]) {
-                                neighbour.setCustomValidity(`Il y a un autre ${neighbour.value} dans cette ${area.name}.`)
-                            }
+            for (area of [
+                {name: "région", neighbours: regions[neighbour1.regionId]},
+                {name: "ligne", neighbours: rows[neighbour1.rowId]},
+                {name: "colonne", neighbours: columns[neighbour1.columnId]},
+            ])
+                for (neighbour2 of area.neighbours)
+                    if (neighbour2 != neighbour1 && neighbour2.value == neighbour1.value) {
+                        for (neighbour of [neighbour1, neighbour2]) {
+                            neighbour.setCustomValidity(`Il y a un autre ${neighbour.value} dans cette ${area.name}.`)
                         }
-            } else {
-                if (neighbour1.candidates.size == 0)
-                    neighbour1.setCustomValidity("Aucun value possible !")
+                    }
+        } else {
+            if (neighbour1.candidates.size == 0) {
+                neighbour1.setCustomValidity("Aucun chiffre possible !")
+                neighbour1.required = true
             }
         }
     }
@@ -131,7 +119,7 @@ function refresh(box) {
             suggestionTimer = setTimeout(showSuggestion, SUGESTION_DELAY)
         }
     } else { // Errors on grid
-        box.reportValidity()
+        box.form.reportValidity()
         box.select()
     }
 }
@@ -216,7 +204,35 @@ function clearAll() {
         box.placeholder = ""
     })
     boxes.forEach(searchCandidatesOf)
-    boxes.forEach(showCandidatesOn)
     enableButtons()
     highlightAndTab()
 }
+
+function oncontextmenu(event) {
+    event.preventDefault()
+    while (contextMenu.firstChild) contextMenu.firstChild.remove()
+    const box = event.target
+    if (box.value == "") {
+        if (box.candidates.size) {
+            candidatesArray = Array.from(box.candidates).sort().forEach(candidate => {
+                li = document.createElement("li")
+                li.innerText = candidate
+                li.onclick = function (event) {
+                    contextMenu.style.display = "none"
+                    box.value = event.target.innerText
+                    refresh(box)
+                }
+                contextMenu.appendChild(li)
+            })
+        } else {
+            li = document.createElement("li")
+            li.innerText = "Aucun chiffre possible"
+            li.className = "error"
+            contextMenu.appendChild(li)
+        }
+        contextMenu.style.left = `${event.pageX}px`
+        contextMenu.style.top = `${event.pageY}px`
+        contextMenu.style.display = "block"
+    }
+    return false
+}
diff --git a/game.php b/game.php
index 42b5156..94dc784 100644
--- a/game.php
+++ b/game.php
@@ -12,7 +12,7 @@
         <meta name='viewport' content='width=device-width' />
         <title>Sudoku</title>
         <link rel='stylesheet' type='text/css' href='style.css' />
-        <script src='sudoku.js'></script>
+        <script src='app.js'></script>
         <link rel="icon" type="image/png" href="favicon.png">
     </head>
     <body>
@@ -38,8 +38,8 @@
                 }
 ?>
                             <td>
-                                <input type='number' min='1' max='9' step='1' value='<?=$value?>' list='<?=$row.$column?>' <?=$disabled?>/>
-                                <datalist id='<?=$row.$column?>'></datalist>
+                                <input type='number' min='1' max='9' step='1' value='<?=$value?>' list='list<?=$row.$column?>' title='[Clic-droit]' <?=$disabled?>/>
+                                <datalist id='list<?=$row.$column?>'></datalist>
                             </td>
 <?php
             }
@@ -67,6 +67,8 @@
         <section>
             Remplissez la grille de sorte que chaque ligne, colonne et région (carré de 3×3 cases) contienne tous les chiffres de 1 à 9.
         </section>
+        <ul id="contextMenu" class="context-menu">
+        </ul>
         <footer>
             <a href=''>Lien vers cette grille</a><br/>
             <a href='.'>Nouvelle grille</a>
@@ -77,9 +79,9 @@
     } else {
     	$grid = new Grid();
     	$grid->generate();
-    
+
         header("HTTP/1.0 400 Bad Request", true, 400);
-    
+
     	$urlDir = $_SERVER["REQUEST_SCHEME"] . "://" . $_SERVER["HTTP_HOST"] . dirname($_SERVER["DOCUMENT_URI"]);
         $urlExample = $urlDir . "/" . $grid->toString();
 ?>
diff --git a/style.css b/style.css
index ca60dff..9e47c86 100644
--- a/style.css
+++ b/style.css
@@ -143,3 +143,38 @@ input[type="color"] {
 a {
     text-decoration: none;
 }
+
+.context-menu {
+    display: none;
+    z-index: 1000;
+    position: absolute;
+    overflow: hidden;
+    border: 1px solid #CCC;
+    white-space: nowrap;
+    font-family: sans-serif;
+    background: #EEE;
+    color: #333;
+    border-radius: 3px;
+    padding: 0;
+}
+
+.context-menu li {
+    padding: 6px 10px;
+    cursor: default;
+    list-style-type: none;
+    transition: all .3s ease;
+    user-select: none;
+    font-size: 0.8em;
+}
+
+.context-menu li:hover {
+    background-color: #DEF;
+}
+
+.context-menu li.error {
+    color: #888
+}
+
+.context-menu li.error:hover {
+    background-color: #EEE;
+}