diff --git a/gerrit-gwtexpui/src/main/java/com/google/gwtexpui/clippy/client/CopyableLabel.java b/gerrit-gwtexpui/src/main/java/com/google/gwtexpui/clippy/client/CopyableLabel.java
index e34814f6ae..a9f437a00d 100644
--- a/gerrit-gwtexpui/src/main/java/com/google/gwtexpui/clippy/client/CopyableLabel.java
+++ b/gerrit-gwtexpui/src/main/java/com/google/gwtexpui/clippy/client/CopyableLabel.java
@@ -127,7 +127,7 @@ public class CopyableLabel extends Composite implements HasText {
   }
 
   private void embedMovie() {
-    if (flashEnabled && UserAgent.hasFlash && text.length() > 0) {
+    if (flashEnabled && !text.isEmpty() && UserAgent.Flash.isInstalled()) {
       final String flashVars = "text=" + URL.encodeQueryString(getText());
       final SafeHtmlBuilder h = new SafeHtmlBuilder();
 
diff --git a/gerrit-gwtexpui/src/main/java/com/google/gwtexpui/user/client/UserAgent.java b/gerrit-gwtexpui/src/main/java/com/google/gwtexpui/user/client/UserAgent.java
index 02ba9aeac5..15983050fe 100644
--- a/gerrit-gwtexpui/src/main/java/com/google/gwtexpui/user/client/UserAgent.java
+++ b/gerrit-gwtexpui/src/main/java/com/google/gwtexpui/user/client/UserAgent.java
@@ -27,26 +27,42 @@ import com.google.gwt.user.client.Window;
  * trivial compared to the time developers lose building their application.
  */
 public class UserAgent {
-  /** Does the browser have ShockwaveFlash plugin enabled? */
-  public static final boolean hasFlash = hasFlash();
+  public static class Flash {
+    private static boolean checked;
+    private static boolean installed;
 
-  private static native boolean hasFlash()
-  /*-{
-    if (navigator.plugins && navigator.plugins.length) {
-      if (navigator.plugins['Shockwave Flash'])     return true;
-      if (navigator.plugins['Shockwave Flash 2.0']) return true;
-
-    } else if (navigator.mimeTypes && navigator.mimeTypes.length) {
-      var mimeType = navigator.mimeTypes['application/x-shockwave-flash'];
-      if (mimeType && mimeType.enabledPlugin) return true;
-
-    } else {
-      try { new ActiveXObject('ShockwaveFlash.ShockwaveFlash.7'); return true; } catch (e) {}
-      try { new ActiveXObject('ShockwaveFlash.ShockwaveFlash.6'); return true; } catch (e) {}
-      try { new ActiveXObject('ShockwaveFlash.ShockwaveFlash');   return true; } catch (e) {}
+    /**
+     * Does the browser have ShockwaveFlash plugin installed?
+     * <p>
+     * This method may still return true if the user has disabled Flash or set
+     * the plugin to "click to run".
+     */
+    public static boolean isInstalled() {
+      if (!checked) {
+        installed = hasFlash();
+        checked = true;
+      }
+      return installed;
     }
-    return false;
-  }-*/;
+
+    private static native boolean hasFlash()
+    /*-{
+      if (navigator.plugins && navigator.plugins.length) {
+        if (navigator.plugins['Shockwave Flash'])     return true;
+        if (navigator.plugins['Shockwave Flash 2.0']) return true;
+
+      } else if (navigator.mimeTypes && navigator.mimeTypes.length) {
+        var mimeType = navigator.mimeTypes['application/x-shockwave-flash'];
+        if (mimeType && mimeType.enabledPlugin) return true;
+
+      } else {
+        try { new ActiveXObject('ShockwaveFlash.ShockwaveFlash.7'); return true; } catch (e) {}
+        try { new ActiveXObject('ShockwaveFlash.ShockwaveFlash.6'); return true; } catch (e) {}
+        try { new ActiveXObject('ShockwaveFlash.ShockwaveFlash');   return true; } catch (e) {}
+      }
+      return false;
+    }-*/;
+  }
 
   /**
    * Test for and disallow running this application in an &lt;iframe&gt;.