diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index bba602d2..997b9216 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -93,7 +93,7 @@
 				  a:label="@string/c_vars_and_constants"
 				  a:configChanges="orientation|keyboardHidden"/>
 
-		<activity a:name=".CalculatorPlotActivity"
+		<activity a:name=".plot.CalculatorPlotActivity"
 				  a:label="@string/c_plot_graph"/>
 
 		<activity a:name="com.google.ads.AdActivity"
diff --git a/res/layout-land/main_calculator.xml b/res/layout-land/main_calculator.xml
index 9a81dc59..267b4d40 100644
--- a/res/layout-land/main_calculator.xml
+++ b/res/layout-land/main_calculator.xml
@@ -53,7 +53,7 @@
 					 a:layout_height="fill_parent"
 					 a:layout_weight="4"/>
 
-			<org.solovyev.android.view.widgets.NumeralBasesButton xmlns:a="http://schemas.android.com/apk/res/android"
+			<org.solovyev.android.calculator.view.NumeralBasesButton xmlns:a="http://schemas.android.com/apk/res/android"
 														   xmlns:c="http://schemas.android.com/apk/res/org.solovyev.android.calculator"
 														   a:id="@+id/clearButton"
 														   c:textUp="dec"
diff --git a/res/layout-land/main_cellphone.xml b/res/layout-land/main_cellphone.xml
index fd84a51b..04f74940 100644
--- a/res/layout-land/main_cellphone.xml
+++ b/res/layout-land/main_cellphone.xml
@@ -47,7 +47,7 @@
 					 a:layout_height="fill_parent"
 					 a:layout_weight="4"/>
 
-			<org.solovyev.android.view.widgets.NumeralBasesButton xmlns:a="http://schemas.android.com/apk/res/android"
+			<org.solovyev.android.calculator.view.NumeralBasesButton xmlns:a="http://schemas.android.com/apk/res/android"
 														   xmlns:c="http://schemas.android.com/apk/res/org.solovyev.android.calculator"
 														   a:id="@+id/clearButton"
 														   c:textUp="dec"
diff --git a/res/layout/calc_clear_button.xml b/res/layout/calc_clear_button.xml
index 237d832b..91033335 100644
--- a/res/layout/calc_clear_button.xml
+++ b/res/layout/calc_clear_button.xml
@@ -6,7 +6,7 @@
   ~ or visit http://se.solovyev.org
   -->
 
-<org.solovyev.android.view.widgets.NumeralBasesButton xmlns:a="http://schemas.android.com/apk/res/android"
+<org.solovyev.android.calculator.view.NumeralBasesButton xmlns:a="http://schemas.android.com/apk/res/android"
 			 xmlns:c="http://schemas.android.com/apk/res/org.solovyev.android.calculator"
 			 a:id="@+id/clearButton"
 			 c:textUp="dec"
diff --git a/res/layout/calc_six_digit_button.xml b/res/layout/calc_six_digit_button.xml
index c0a23af3..fc6b73ea 100644
--- a/res/layout/calc_six_digit_button.xml
+++ b/res/layout/calc_six_digit_button.xml
@@ -6,7 +6,7 @@
   ~ or visit http://se.solovyev.org
   -->
 
-<org.solovyev.android.view.widgets.AngleUnitsButton xmlns:a="http://schemas.android.com/apk/res/android"
+<org.solovyev.android.calculator.view.AngleUnitsButton xmlns:a="http://schemas.android.com/apk/res/android"
 													   xmlns:c="http://schemas.android.com/apk/res/org.solovyev.android.calculator"
 													   c:textUp="deg"
 													   a:id="@+id/sixDigitButton"
diff --git a/src/main/java/org/solovyev/android/calculator/CalculatorActivity.java b/src/main/java/org/solovyev/android/calculator/CalculatorActivity.java
index 4d50d318..207984a7 100644
--- a/src/main/java/org/solovyev/android/calculator/CalculatorActivity.java
+++ b/src/main/java/org/solovyev/android/calculator/CalculatorActivity.java
@@ -37,6 +37,8 @@ import org.solovyev.android.calculator.history.CalculatorHistory;
 import org.solovyev.android.calculator.history.CalculatorHistoryState;
 import org.solovyev.android.calculator.math.MathType;
 import org.solovyev.android.calculator.model.CalculatorEngine;
+import org.solovyev.android.calculator.view.AngleUnitsButton;
+import org.solovyev.android.calculator.view.NumeralBasesButton;
 import org.solovyev.android.view.FontSizeAdjuster;
 import org.solovyev.android.view.prefs.IntegerPreference;
 import org.solovyev.android.view.prefs.Preference;
@@ -126,6 +128,10 @@ public class CalculatorActivity extends Activity implements FontSizeAdjuster, Sh
 		}
 
 		ResourceCache.instance.initCaptions(CalculatorApplication.getInstance(), R.string.class);
+
+		billingObserver = new CalculatorBillingObserver(this);
+		BillingController.registerObserver(billingObserver);
+
 		firstTimeInit(preferences);
 
 		// init billing controller
@@ -385,9 +391,6 @@ public class CalculatorActivity extends Activity implements FontSizeAdjuster, Sh
 	private synchronized void firstTimeInit(@NotNull SharedPreferences preferences) {
 		if (!initialized) {
 
-			billingObserver = new CalculatorBillingObserver(this);
-			BillingController.registerObserver(billingObserver);
-
 			final int savedVersion = Preferences.appVersion.getPreference(preferences);
 
 			final int appVersion = AndroidUtils.getAppVersionCode(this, CalculatorActivity.class.getPackage().getName());
diff --git a/src/main/java/org/solovyev/android/calculator/CalculatorActivityLauncher.java b/src/main/java/org/solovyev/android/calculator/CalculatorActivityLauncher.java
index 95599dd4..67951e3f 100644
--- a/src/main/java/org/solovyev/android/calculator/CalculatorActivityLauncher.java
+++ b/src/main/java/org/solovyev/android/calculator/CalculatorActivityLauncher.java
@@ -14,6 +14,7 @@ import org.solovyev.android.calculator.math.edit.CalculatorFunctionsTabActivity;
 import org.solovyev.android.calculator.math.edit.CalculatorOperatorsActivity;
 import org.solovyev.android.calculator.math.edit.CalculatorVarsTabActivity;
 import org.solovyev.android.calculator.math.edit.CalculatorVarsActivity;
+import org.solovyev.android.calculator.plot.CalculatorPlotActivity;
 import org.solovyev.common.utils.StringUtils;
 
 /**
diff --git a/src/main/java/org/solovyev/android/calculator/CalculatorDisplay.java b/src/main/java/org/solovyev/android/calculator/CalculatorDisplay.java
index 0d6b8ff2..b87c79dd 100644
--- a/src/main/java/org/solovyev/android/calculator/CalculatorDisplay.java
+++ b/src/main/java/org/solovyev/android/calculator/CalculatorDisplay.java
@@ -19,6 +19,7 @@ import org.solovyev.android.calculator.jscl.JsclOperation;
 import org.solovyev.android.calculator.model.CalculatorEngine;
 import org.solovyev.android.calculator.model.CalculatorParseException;
 import org.solovyev.android.calculator.model.TextProcessor;
+import org.solovyev.android.calculator.view.TextHighlighter;
 import org.solovyev.android.view.AMenuItem;
 import org.solovyev.android.view.AutoResizeTextView;
 
diff --git a/src/main/java/org/solovyev/android/calculator/CalculatorEditor.java b/src/main/java/org/solovyev/android/calculator/CalculatorEditor.java
index 9e659742..dc8ec073 100644
--- a/src/main/java/org/solovyev/android/calculator/CalculatorEditor.java
+++ b/src/main/java/org/solovyev/android/calculator/CalculatorEditor.java
@@ -18,8 +18,8 @@ import org.jetbrains.annotations.NotNull;
 import org.solovyev.android.calculator.model.CalculatorEngine;
 import org.solovyev.android.calculator.model.CalculatorParseException;
 import org.solovyev.android.calculator.model.TextProcessor;
+import org.solovyev.android.calculator.view.TextHighlighter;
 import org.solovyev.common.utils.CollectionsUtils;
-import org.solovyev.common.utils.StringUtils;
 
 /**
  * User: serso
diff --git a/src/main/java/org/solovyev/android/calculator/StartsWithFinder.java b/src/main/java/org/solovyev/android/calculator/StartsWithFinder.java
deleted file mode 100644
index c4e7b94e..00000000
--- a/src/main/java/org/solovyev/android/calculator/StartsWithFinder.java
+++ /dev/null
@@ -1,38 +0,0 @@
-/*
- * Copyright (c) 2009-2011. Created by serso aka se.solovyev.
- * For more information, please, contact se.solovyev@gmail.com
- * or visit http://se.solovyev.org
- */
-
-package org.solovyev.android.calculator;
-
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
-import org.solovyev.common.utils.Finder;
-
-/**
-* User: serso
-* Date: 10/3/11
-* Time: 12:49 AM
-*/
-public class StartsWithFinder implements Finder<String> {
-
-	private int i;
-
-	@NotNull
-	private final String targetString;
-
-	public StartsWithFinder(@NotNull String targetString, int i) {
-		this.targetString = targetString;
-		this.i = i;
-	}
-
-	@Override
-	public boolean isFound(@Nullable String s) {
-		return targetString.startsWith(s, i);
-	}
-
-	public void setI(int i) {
-		this.i = i;
-	}
-}
diff --git a/src/main/java/org/solovyev/android/calculator/math/MathType.java b/src/main/java/org/solovyev/android/calculator/math/MathType.java
index 5db95224..b9321fdc 100644
--- a/src/main/java/org/solovyev/android/calculator/math/MathType.java
+++ b/src/main/java/org/solovyev/android/calculator/math/MathType.java
@@ -10,7 +10,7 @@ import jscl.NumeralBase;
 import jscl.math.function.Constants;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
-import org.solovyev.android.calculator.StartsWithFinder;
+import org.solovyev.common.StartsWithFinder;
 import org.solovyev.android.calculator.model.CalculatorEngine;
 import org.solovyev.android.calculator.model.CalculatorParseException;
 import org.solovyev.common.utils.CollectionsUtils;
diff --git a/src/main/java/org/solovyev/android/calculator/model/ToJsclTextProcessor.java b/src/main/java/org/solovyev/android/calculator/model/ToJsclTextProcessor.java
index d2d055e0..9fd64ac4 100644
--- a/src/main/java/org/solovyev/android/calculator/model/ToJsclTextProcessor.java
+++ b/src/main/java/org/solovyev/android/calculator/model/ToJsclTextProcessor.java
@@ -8,7 +8,7 @@ package org.solovyev.android.calculator.model;
 
 import jscl.math.function.IConstant;
 import org.jetbrains.annotations.NotNull;
-import org.solovyev.android.calculator.StartsWithFinder;
+import org.solovyev.common.StartsWithFinder;
 import org.solovyev.android.calculator.math.MathType;
 import org.solovyev.common.utils.CollectionsUtils;
 
diff --git a/src/main/java/org/solovyev/android/calculator/CalculatorPlotActivity.java b/src/main/java/org/solovyev/android/calculator/plot/CalculatorPlotActivity.java
similarity index 98%
rename from src/main/java/org/solovyev/android/calculator/CalculatorPlotActivity.java
rename to src/main/java/org/solovyev/android/calculator/plot/CalculatorPlotActivity.java
index 8d0080e0..63ffc3a7 100644
--- a/src/main/java/org/solovyev/android/calculator/CalculatorPlotActivity.java
+++ b/src/main/java/org/solovyev/android/calculator/plot/CalculatorPlotActivity.java
@@ -4,7 +4,7 @@
  * or visit http://se.solovyev.org
  */
 
-package org.solovyev.android.calculator;
+package org.solovyev.android.calculator.plot;
 
 import android.app.Activity;
 import android.graphics.Color;
@@ -33,8 +33,7 @@ import org.achartengine.tools.ZoomEvent;
 import org.achartengine.tools.ZoomListener;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
-import org.solovyev.android.calculator.plot.MyXYSeries;
-import org.solovyev.android.calculator.plot.PlotUtils;
+import org.solovyev.android.calculator.R;
 import org.solovyev.common.utils.MutableObject;
 
 import java.io.Serializable;
diff --git a/src/main/java/org/solovyev/android/view/widgets/AngleUnitsButton.java b/src/main/java/org/solovyev/android/calculator/view/AngleUnitsButton.java
similarity index 92%
rename from src/main/java/org/solovyev/android/view/widgets/AngleUnitsButton.java
rename to src/main/java/org/solovyev/android/calculator/view/AngleUnitsButton.java
index 4a3bd30e..24852c4c 100644
--- a/src/main/java/org/solovyev/android/view/widgets/AngleUnitsButton.java
+++ b/src/main/java/org/solovyev/android/calculator/view/AngleUnitsButton.java
@@ -4,7 +4,7 @@
  * or visit http://se.solovyev.org
  */
 
-package org.solovyev.android.view.widgets;
+package org.solovyev.android.calculator.view;
 
 import android.content.Context;
 import android.content.res.Resources;
@@ -14,6 +14,7 @@ import android.util.AttributeSet;
 import org.jetbrains.annotations.NotNull;
 import org.solovyev.android.calculator.R;
 import org.solovyev.android.calculator.model.CalculatorEngine;
+import org.solovyev.android.view.widgets.DirectionDragButton;
 
 /**
  * User: serso
diff --git a/src/main/java/org/solovyev/android/view/widgets/NumeralBasesButton.java b/src/main/java/org/solovyev/android/calculator/view/NumeralBasesButton.java
similarity index 92%
rename from src/main/java/org/solovyev/android/view/widgets/NumeralBasesButton.java
rename to src/main/java/org/solovyev/android/calculator/view/NumeralBasesButton.java
index 1160bdd6..200bf4f1 100644
--- a/src/main/java/org/solovyev/android/view/widgets/NumeralBasesButton.java
+++ b/src/main/java/org/solovyev/android/calculator/view/NumeralBasesButton.java
@@ -4,7 +4,7 @@
  * or visit http://se.solovyev.org
  */
 
-package org.solovyev.android.view.widgets;
+package org.solovyev.android.calculator.view;
 
 import android.content.Context;
 import android.content.res.Resources;
@@ -14,6 +14,7 @@ import android.util.AttributeSet;
 import org.jetbrains.annotations.NotNull;
 import org.solovyev.android.calculator.R;
 import org.solovyev.android.calculator.model.CalculatorEngine;
+import org.solovyev.android.view.widgets.DirectionDragButton;
 
 /**
  * User: serso
diff --git a/src/main/java/org/solovyev/android/calculator/TextHighlighter.java b/src/main/java/org/solovyev/android/calculator/view/TextHighlighter.java
similarity index 99%
rename from src/main/java/org/solovyev/android/calculator/TextHighlighter.java
rename to src/main/java/org/solovyev/android/calculator/view/TextHighlighter.java
index b535bebf..f8572d9e 100644
--- a/src/main/java/org/solovyev/android/calculator/TextHighlighter.java
+++ b/src/main/java/org/solovyev/android/calculator/view/TextHighlighter.java
@@ -4,7 +4,7 @@
  * or visit http://se.solovyev.org
  */
 
-package org.solovyev.android.calculator;
+package org.solovyev.android.calculator.view;
 
 import jscl.MathContext;
 import org.jetbrains.annotations.NotNull;
diff --git a/src/test/java/org/solovyev/android/calculator/TextHighlighterTest.java b/src/test/java/org/solovyev/android/calculator/TextHighlighterTest.java
index 1fd99072..12413380 100644
--- a/src/test/java/org/solovyev/android/calculator/TextHighlighterTest.java
+++ b/src/test/java/org/solovyev/android/calculator/TextHighlighterTest.java
@@ -13,6 +13,7 @@ import junit.framework.Assert;
 import org.junit.Test;
 import org.solovyev.android.calculator.model.CalculatorEngine;
 import org.solovyev.android.calculator.model.TextProcessor;
+import org.solovyev.android.calculator.view.TextHighlighter;
 
 import java.util.Date;
 import java.util.Random;