This is an Android Development related question.
I make use of the ADT and Eclipse Indigo in a Windows 7 64bits

First we have the xml layout file:

```
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:orientation="vertical">

  <EditText
    android:id="@+id/editText1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:ems="10" >
  </EditText>

</LinearLayout>

```

Second, we have the class that makes a reference to the xml file right above

```
package com.example.test_table;

import android.os.Bundle;
import android.app.Activity;

public class Home extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_home);

    }

}

```

In third place, we got the declaration in the manifest of the class Home

```
<activity
    android:name="com.example.test_table.Home"
    android:label="@string/app_name" >
    <intent-filter>
        <action android:name="android.intent.action.MAIN" />
        <category android:name="android.intent.category.LAUNCHER" />
    </intent-filter>
 </activity>

```

And then, when I try to run, Eclipse returns a nullpointerexception.
But when I remove the EditText from the xml layout file, the application works.
This problem suddenly appeared in my computer and I'm trying to do something about it. 

LogCat:

```
02-27 22:42:39.051: E/AndroidRuntime(12164): FATAL EXCEPTION: main
02-27 22:42:39.051: E/AndroidRuntime(12164): java.lang.RuntimeException: Unable to start activity ComponentInfo {com.example.test_table/com.example.test_table.Home}: java.lang.NullPointerException
02-27 22:42:39.051: E/AndroidRuntime(12164):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1970)
02-27 22:42:39.051: E/AndroidRuntime(12164):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1995)
02-27 22:42:39.051: E/AndroidRuntime(12164):    at android.app.ActivityThread.access$600(ActivityThread.java:128)
02-27 22:42:39.051: E/AndroidRuntime(12164):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1161)
02-27 22:42:39.051: E/AndroidRuntime(12164):    at android.os.Handler.dispatchMessage(Handler.java:99)
02-27 22:42:39.051: E/AndroidRuntime(12164):    at android.os.Looper.loop(Looper.java:137)
02-27 22:42:39.051: E/AndroidRuntime(12164):    at android.app.ActivityThread.main(ActivityThread.java:4514)
02-27 22:42:39.051: E/AndroidRuntime(12164):    at java.lang.reflect.Method.invokeNative(Native Method)
02-27 22:42:39.051: E/AndroidRuntime(12164):    at java.lang.reflect.Method.invoke(Method.java:511)
02-27 22:42:39.051: E/AndroidRuntime(12164):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:790)
02-27 22:42:39.051: E/AndroidRuntime(12164):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:557)
02-27 22:42:39.051: E/AndroidRuntime(12164):    at dalvik.system.NativeStart.main(Native Method)
02-27 22:42:39.051: E/AndroidRuntime(12164): Caused by: java.lang.NullPointerException
02-27 22:42:39.051: E/AndroidRuntime(12164):    at android.sec.clipboard.ClipboardExManager.updateData(ClipboardExManager.java:241)
02-27 22:42:39.051: E/AndroidRuntime(12164):    at android.widget.EditText.onFocusChanged(EditText.java:134)
02-27 22:42:39.051: E/AndroidRuntime(12164):    at android.view.View.handleFocusGainInternal(View.java:3727)
02-27 22:42:39.051: E/AndroidRuntime(12164):    at android.view.View.requestFocus(View.java:5420)
02-27 22:42:39.051: E/AndroidRuntime(12164):    at android.view.View.requestFocus(View.java:5370)
02-27 22:42:39.051: E/AndroidRuntime(12164):    at android.view.View.requestFocus(View.java:5348)
02-27 22:42:39.051: E/AndroidRuntime(12164):    at android.view.LayoutInflater.parseRequestFocus(LayoutInflater.java:753)
02-27 22:42:39.051: E/AndroidRuntime(12164):    at android.view.LayoutInflater.rInflate(LayoutInflater.java:724)
02-27 22:42:39.051: E/AndroidRuntime(12164):    at android.view.LayoutInflater.rInflate(LayoutInflater.java:742)
02-27 22:42:39.051: E/AndroidRuntime(12164):    at android.view.LayoutInflater.inflate(LayoutInflater.java:489)
02-27 22:42:39.051: E/AndroidRuntime(12164):    at android.view.LayoutInflater.inflate(LayoutInflater.java:396)
02-27 22:42:39.051: E/AndroidRuntime(12164):    at android.view.LayoutInflater.inflate(LayoutInflater.java:352)
02-27 22:42:39.051: E/AndroidRuntime(12164):    at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:273)
02-27 22:42:39.051: E/AndroidRuntime(12164):    at android.app.Activity.setContentView(Activity.java:1835)
02-27 22:42:39.051: E/AndroidRuntime(12164):    at com.example.test_table.Home.onCreate(Home.java:11)
02-27 22:42:39.051: E/AndroidRuntime(12164):    at android.app.Activity.performCreate(Activity.java:4465)
02-27 22:42:39.051: E/AndroidRuntime(12164):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1053)
02-27 22:42:39.051: E/AndroidRuntime(12164):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1934)
02-27 22:42:39.051: E/AndroidRuntime(12164):    ... 11 more

```

So, I'd like to know what causes the ADT to stop recognizing an Edittext?