i try to use 2 themes in one activity,one for dialog and one for hiding the title bar, in the AndroidManifest:

```
<activity>
  android:theme="@android:style/Theme.Dialog" 
    android:theme="@android:style/Theme.Black.NoTitleBar"
    android:label="@string/app_name" > (it show X here!!)
    <intent-filter>
        <action android:name="android.intent.action.MAIN" />
        <category android:name="android.intent.category.LAUNCHER" />
    </intent-filter>
</activity>

```

i can only use one at a time...