XML : Very small SwitchPreference button

Here's my preferences.xml file:

  <PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android" >  <PreferenceCategory android:title="@string/prefs_settings">      <SwitchPreference          android:key="SP_SETTINGS"          android:title="@string/prefs_settings_reload"          android:summaryOn="@string/prefs_settings_reload_summary_on"          android:switchTextOff="OFF"          android:switchTextOn="ON"          android:defaultValue="false"/>  </PreferenceCategory>  <PreferenceCategory android:title="@string/prefs_user_settings" >      <CheckBoxPreference          android:key="SP_SAVE_AUTO"          android:title="@string/prefs_saveauto"          android:summary="@string/prefs_saveauto_summary"          android:defaultValue="true"/>  </PreferenceCategory>  <PreferenceCategory android:title="@string/prefs_server_settings" >      <CheckBoxPreference          android:key="SP_DEV_SERVER"          android:title="@string/prefs_server_title"          android:summary="@string/prefs_server_summary"          android:defaultValue="false"/>      <EditTextPreference          android:key="SP_DEV_NUMBER"          android:title="@string/prefs_server_number"          android:summary="@string/prefs_server_number_summary"          android:defaultValue="50"/>      <EditTextPreference          android:key="wSP_DEV_PASSWORD"          android:password="true"          android:summary="@string/prefs_server_password_summary"          android:title="@string/prefs_server_password" />  </PreferenceCategory>    

The thing is, my switch preference is black and small, so we can't see it. Usually, the button is blue and quite big, so I don't understand why it's not since I haven't played with much settings. Any clue to help me?