Index: gc_lang/fr/webext/content_scripts/panel.css
==================================================================
--- gc_lang/fr/webext/content_scripts/panel.css
+++ gc_lang/fr/webext/content_scripts/panel.css
@@ -83,25 +83,29 @@
     padding: 1px 5px;
     border-radius: 16px;
     color: hsl(180, 0%, 100%);
     opacity: .5;
 }
+div.grammalecte_move_button_center {
+    padding: 1px 10px;
+    background: center no-repeat url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" width="12" height="12"><circle fill="%23fff" cx="6" cy="6" r="4"/></svg>') ;
+}
 div.grammalecte_move_button_up {
     padding: 1px 10px;
-    background: center no-repeat url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAwAAAAMCAYAAABWdVznAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAAYdEVYdFNvZnR3YXJlAHBhaW50Lm5ldCA0LjEuNv1OCegAAABcSURBVChTlY67DcAgDEQZhg3oGJMuA9CzoTlbcoQT8zvpFX7cSQQiusKVK1wJCkgfJ/wE4LImA/NuDjCWNWY0lh8wyzvScgW7yIjLTc6zZB7EG/RLx7hyhSvnUOgfudLrksye1QAAAABJRU5ErkJggg==');
+    background: center no-repeat url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" width="12" height="12"><path fill="%23fff" d="m 6,2 6,6 h -12"/></svg>');
 }
 div.grammalecte_move_button_right {
     padding: 1px 10px;
-    background: center no-repeat url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAwAAAAMCAYAAABWdVznAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAAYdEVYdFNvZnR3YXJlAHBhaW50Lm5ldCA0LjEuNv1OCegAAABlSURBVChTdYs5DoBADAP3hzT0/IyWlpaSlwUHbaIc3pGmSGwPEake5Oeyp7JDli0HygZb3h4w0kbpmFbSKBZNho9qWWWc8M9rWa1c0PNYNCM3THk6psYDW94eUHkhy+hgWRaR8QHurtJh4OI9JwAAAABJRU5ErkJggg==');
+    background: center no-repeat url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" width="12" height="12"><path fill="%23fff" d="m 2,0 6,6 -6,6"/></svg>');
 }
 div.grammalecte_move_button_down {
     padding: 1px 10px;
-    background: center no-repeat url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAwAAAAMCAYAAABWdVznAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAAYdEVYdFNvZnR3YXJlAHBhaW50Lm5ldCA0LjEuNv1OCegAAABcSURBVChTY/j//z9JGKsgPoxVEB/GKogPg4jrJOBKkAYzICYGbAdiuJMIaVoNxHAnEdK0AIjh6pA1gDC6pjlAjKIGhQPFpkAMAhiKQRhDAIqVsYiBMVZB3Pg/AwAQkdVnCojycwAAAABJRU5ErkJggg==');
+    background: center no-repeat url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" width="12" height="12"><path fill="%23fff" d="m 0,2 6,6 6,-6"/></svg>');
 }
 div.grammalecte_move_button_left {
     padding: 1px 10px;
-    background: center no-repeat url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAwAAAAMCAYAAABWdVznAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAAYdEVYdFNvZnR3YXJlAHBhaW50Lm5ldCA0LjEuNv1OCegAAABaSURBVChTY/j//z8+3IguhsJBw/eBeB+aGE4N14AYBIjScBaIYYCghsNAjAzwatgFxOgApwZ9IMYG8NqATRNBP6BrIqgBhJE1EaUBhGGaiNYAwkZAjKbhPwMAP5rVDlUnDt8AAAAASUVORK5CYII=');
+    background: center no-repeat url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" width="12" height="12"><path fill="%23fff" d="m 2,6 6,6 v -12"/></svg>');
 }
 div.grammalecte_move_button:hover {
     background-color: hsla(180, 80%, 50%, .1);
     color: hsla(180, 0%, 100%, 1);
     opacity: 1;

Index: gc_lang/fr/webext/content_scripts/panel.js
==================================================================
--- gc_lang/fr/webext/content_scripts/panel.js
+++ gc_lang/fr/webext/content_scripts/panel.js
@@ -74,11 +74,11 @@
             xButtonLine.appendChild(this._createMoveButton("changeWidth", "⭾", "Bascule la largeur"));
             xButtonLine.appendChild(this._createMoveButton("changeHeight", "⭿", "Bascule la hauteur"));
         }
         xButtonLine.appendChild(this._createMoveButton("up", " ", "Monter")); // use char ⏶ when Windows 10 be vast majority of OS (Trebuchet MS not updated on other OS)
         xButtonLine.appendChild(this._createMoveButton("left", " ", "À gauche")); // use char ⏴ when Windows 10 be vast majority of OS (Trebuchet MS not updated on other OS)
-        xButtonLine.appendChild(this._createMoveButton("center", "•", "Centrer"));
+        xButtonLine.appendChild(this._createMoveButton("center", " ", "Centrer")); // char • can be used already
         xButtonLine.appendChild(this._createMoveButton("right", " ", "À droite")); // use char ⏵ when Windows 10 be vast majority of OS (Trebuchet MS not updated on other OS)
         xButtonLine.appendChild(this._createMoveButton("down", " ", "Descendre")); // use char ⏷ when Windows 10 be vast majority of OS (Trebuchet MS not updated on other OS)
         this.xCloseButton = this._createCloseButton();
         xButtonLine.appendChild(this.xCloseButton);
         return xButtonLine;