diff --git a/common/content/commandline.js b/common/content/commandline.js
index 0ffd2bbe..acc0c09a 100644
--- a/common/content/commandline.js
+++ b/common/content/commandline.js
@@ -912,7 +912,7 @@ var CommandLine = Module("commandline", {
          * @param {string} val The new value.
          */
         replace: function replace(val) {
-            delete this.input.dactylKeyPress;
+            this.input.dactylKeyPress = undefined;
             if (this.completions)
                 this.completions.previewClear();
             this.input.value = val;
@@ -1031,7 +1031,7 @@ var CommandLine = Module("commandline", {
             this.caret = this.prefix.length + completion.length;
             this._caret = this.caret;
 
-            delete this.input.dactylKeyPress;
+            this.input.dactylKeyPress = undefined;
         },
 
         get caret() this.editor.selection.getRangeAt(0).startOffset,
diff --git a/common/content/events.js b/common/content/events.js
index 168e6a59..0bf5e0fc 100644
--- a/common/content/events.js
+++ b/common/content/events.js
@@ -1026,7 +1026,7 @@ var Events = Module("events", {
                 let elem = event.originalTarget;
                 elem.dactylKeyPress = elem.value;
                 util.timeout(function () {
-                    if (elem.value !== elem.dactylKeyPress)
+                    if (elem.dactylKeyPress !== undefined && elem.value !== elem.dactylKeyPress)
                         events.dispatch(elem, events.create(elem.ownerDocument, "input"));
                     delete events.dactylKeyPress;
                 });