diff --git a/toolkit/components/satchel/AutoCompleteE10S.jsm b/toolkit/components/satchel/AutoCompleteE10S.jsm
index 79d4911d66ba..94365e7341ed 100644
--- a/toolkit/components/satchel/AutoCompleteE10S.jsm
+++ b/toolkit/components/satchel/AutoCompleteE10S.jsm
@@ -93,7 +93,8 @@ this.AutoCompleteE10S = {
     this.browser = browserWindow.gBrowser.selectedBrowser;
     this.popup = this.browser.autoCompletePopup;
     this.popup.hidden = false;
-    this.popup.setAttribute("width", rect.width);
+    // don't allow the popup to become overly narrow
+    this.popup.setAttribute("width", Math.max(100, rect.width));
     this.popup.style.direction = direction;
 
     this.x = rect.left;