--- a/dom/base/nsDOMWindowUtils.cpp
+++ b/dom/base/nsDOMWindowUtils.cpp
@@ -3589,17 +3589,17 @@ nsDOMWindowUtils::GetIsHandlingUserInput
   return NS_OK;
 }
 
 NS_IMETHODIMP
 nsDOMWindowUtils::GetMillisSinceLastUserInput(double* aMillisSinceLastUserInput)
 {
   TimeStamp lastInput = EventStateManager::LatestUserInputStart();
   if (lastInput.IsNull()) {
-    *aMillisSinceLastUserInput = 0;
+    *aMillisSinceLastUserInput = -1.0f;
     return NS_OK;
   }
 
   *aMillisSinceLastUserInput = (TimeStamp::Now() - lastInput).ToMilliseconds();
   return NS_OK;
 }
 
 NS_IMETHODIMP

--- a/dom/interfaces/base/nsIDOMWindowUtils.idl
+++ b/dom/interfaces/base/nsIDOMWindowUtils.idl
@@ -1644,17 +1644,18 @@ interface nsIDOMWindowUtils : nsISupport
   /**
    * Returns true if a user input is being handled.
    *
    * This calls EventStateManager::IsHandlingUserInput().
    */
   readonly attribute boolean isHandlingUserInput;
 
   /**
-   * Returns milliseconds elapsed since last user input was started
+   * Returns milliseconds elapsed since last user input was started.
+   * Returns -1 if there wasn't any previous user input.
    *
    * This relies on EventStateManager::LatestUserInputStart()
    */
   readonly attribute double millisSinceLastUserInput;
 
   /**
    * After calling the method, the window for which this DOMWindowUtils
    * was created can be closed using scripts.

--- a/mobile/android/components/ContentDispatchChooser.js
+++ b/mobile/android/components/ContentDispatchChooser.js
@@ -80,17 +80,17 @@ ContentDispatchChooser.prototype =
           return;
         }
 
         // We couldn't open this. If this was from a click, it's likely that we just
         // want this to fail silently. If the user entered this on the address bar, though,
         // we want to show the neterror page.
         let dwu = window.QueryInterface(Ci.nsIInterfaceRequestor).getInterface(Ci.nsIDOMWindowUtils);
         let millis = dwu.millisSinceLastUserInput;
-        if (millis > 0 && millis >= 1000) {
+        if (millis < 0 || millis >= 1000) {
           window.location.href = data.uri;
         } else {
           this._closeBlankWindow(window);
         }
       });
     }
   },
 };