diff --git a/src/ZenSidebarManager.mjs b/src/ZenSidebarManager.mjs
index abde7e1..b508292 100644
--- a/src/ZenSidebarManager.mjs
+++ b/src/ZenSidebarManager.mjs
@@ -22,6 +22,8 @@ var gZenBrowserManagerSidebar = {
     ChromeUtils.defineLazyGetter(this, 'forwardButton', () => document.getElementById('zen-sidebar-web-panel-forward'));
     ChromeUtils.defineLazyGetter(this, 'backButton', () => document.getElementById('zen-sidebar-web-panel-back'));
 
+    this.onlySafeWidthAndHeight();
+
     this.initProgressListener();
     this.update();
     this.close(); // avoid caching
@@ -30,6 +32,15 @@ var gZenBrowserManagerSidebar = {
     this.addPositioningListeners();
   },
 
+  onlySafeWidthAndHeight() {
+    const panel = document.getElementById('zen-sidebar-web-panel');
+    const width = panel.style.width;
+    const height = panel.style.height;
+    panel.setAttribute('style', "");
+    panel.style.width = width;
+    panel.style.height = height;
+  },
+
   initProgressListener() {
     this.progressListener  = {
       QueryInterface: ChromeUtils.generateQI([