diff --git a/android-app/AndroidManifest.xml b/android-app/AndroidManifest.xml
index db7ca808..66a63eab 100644
--- a/android-app/AndroidManifest.xml
+++ b/android-app/AndroidManifest.xml
@@ -72,7 +72,11 @@
 		<activity android:name=".CalculatorDialogActivity" android:theme="@style/cpp_metro_blue_dialog_theme"/>
 
 		<!-- todo serso: strings-->
-		<activity android:label="@string/c_plot_graph" android:name=".matrix.CalculatorMatrixActivity"/>
+		<activity android:label="@string/c_plot_graph" android:name=".matrix.CalculatorMatrixActivity">
+			<intent-filter>
+				<action android:name="android.intent.action.MAIN"/>
+			</intent-filter>
+		</activity>
 
 		<activity android:name=".widget.CalculatorWidgetConfigurationActivity" android:theme="@style/cpp_metro_blue_theme">
 			<intent-filter>
diff --git a/android-app/src/main/java/org/solovyev/android/calculator/matrix/CalculatorMatrixEditFragment.java b/android-app/src/main/java/org/solovyev/android/calculator/matrix/CalculatorMatrixEditFragment.java
index b7e5cde4..2dbfcb25 100644
--- a/android-app/src/main/java/org/solovyev/android/calculator/matrix/CalculatorMatrixEditFragment.java
+++ b/android-app/src/main/java/org/solovyev/android/calculator/matrix/CalculatorMatrixEditFragment.java
@@ -24,17 +24,14 @@ package org.solovyev.android.calculator.matrix;
 
 import android.os.Bundle;
 import android.view.View;
-
-import javax.annotation.Nonnull;
-import javax.annotation.Nullable;
-
 import org.solovyev.android.calculator.CalculatorFragment;
 import org.solovyev.android.calculator.CalculatorFragmentType;
 import org.solovyev.android.calculator.R;
 import org.solovyev.android.view.IntegerRange;
 import org.solovyev.android.view.Picker;
 
-import java.io.Serializable;
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
 
 /**
  * User: Solovyev_S
@@ -91,11 +88,11 @@ public class CalculatorMatrixEditFragment extends CalculatorFragment implements
 		final Picker<Integer> matrixColsCountPicker = (Picker<Integer>) root.findViewById(R.id.matrix_cols_count_picker);
 		initPicker(matrixColsCountPicker);
 
-		Matrix matrix = null;
+		MatrixUi matrix = null;
 		if (in != null) {
 			final Object matrixObject = in.getSerializable(MATRIX);
-			if (matrixObject instanceof Matrix) {
-				matrix = (Matrix) matrixObject;
+			if (matrixObject instanceof MatrixUi) {
+				matrix = (MatrixUi) matrixObject;
 			}
 		}
 
@@ -103,7 +100,7 @@ public class CalculatorMatrixEditFragment extends CalculatorFragment implements
 		if (matrix == null) {
 			matrixView.setMatrixDimensions(DEFAULT_ROWS, DEFAULT_COLS);
 		} else {
-			matrixView.setMatrix(matrix.bakingArray);
+			matrixView.setMatrix(matrix.getBakingArray());
 		}
 		matrixRowsCountPicker.setCurrent(matrixView.getRows());
 		matrixColsCountPicker.setCurrent(matrixView.getCols());
@@ -113,7 +110,7 @@ public class CalculatorMatrixEditFragment extends CalculatorFragment implements
 	public void onSaveInstanceState(@Nonnull Bundle out) {
 		super.onSaveInstanceState(out);
 
-		out.putSerializable(MATRIX, new Matrix(getMatrixView(getView()).toMatrix()));
+		out.putSerializable(MATRIX, new MatrixUi(getMatrixView(getView()).toMatrix()));
 	}
 
 	@Nonnull
@@ -146,16 +143,4 @@ public class CalculatorMatrixEditFragment extends CalculatorFragment implements
 		getMatrixView(getView()).setMatrixRows(newRows);
 	}
 
-	public static class Matrix implements Serializable {
-
-		@Nonnull
-		private String[][] bakingArray;
-
-		public Matrix() {
-		}
-
-		public Matrix(@Nonnull String[][] bakingArray) {
-			this.bakingArray = bakingArray;
-		}
-	}
 }
diff --git a/android-app/src/main/java/org/solovyev/android/calculator/matrix/MatrixUi.java b/android-app/src/main/java/org/solovyev/android/calculator/matrix/MatrixUi.java
new file mode 100644
index 00000000..22a76100
--- /dev/null
+++ b/android-app/src/main/java/org/solovyev/android/calculator/matrix/MatrixUi.java
@@ -0,0 +1,27 @@
+package org.solovyev.android.calculator.matrix;
+
+import javax.annotation.Nonnull;
+import java.io.Serializable;
+
+/**
+* User: serso
+* Date: 7/11/13
+* Time: 4:54 PM
+*/
+class MatrixUi implements Serializable {
+
+	@Nonnull
+	private String[][] bakingArray;
+
+	public MatrixUi() {
+	}
+
+	public MatrixUi(@Nonnull String[][] bakingArray) {
+		this.bakingArray = bakingArray;
+	}
+
+	@Nonnull
+	String[][] getBakingArray() {
+		return bakingArray;
+	}
+}
diff --git a/android-app/src/main/java/org/solovyev/android/calculator/matrix/MatrixView.java b/android-app/src/main/java/org/solovyev/android/calculator/matrix/MatrixView.java
index 10cfa4e8..9e2a099d 100644
--- a/android-app/src/main/java/org/solovyev/android/calculator/matrix/MatrixView.java
+++ b/android-app/src/main/java/org/solovyev/android/calculator/matrix/MatrixView.java
@@ -118,8 +118,8 @@ public class MatrixView extends TableLayout {
 			throw new IllegalArgumentException("Number of columns must be more than 1: " + newCols);
 		}
 
-		boolean rowsChanged = this.rows != newRows;
-		boolean colsChanged = this.cols != newCols;
+		final boolean rowsChanged = this.rows != newRows;
+		final boolean colsChanged = this.cols != newCols;
 
 		if (rowsChanged || colsChanged) {
 			if (!initialized) {
diff --git a/android-app/src/test/java/org/solovyev/android/calculator/matrix/MatrixViewTest.java b/android-app/src/test/java/org/solovyev/android/calculator/matrix/MatrixViewTest.java
new file mode 100644
index 00000000..721d90a9
--- /dev/null
+++ b/android-app/src/test/java/org/solovyev/android/calculator/matrix/MatrixViewTest.java
@@ -0,0 +1,9 @@
+package org.solovyev.android.calculator.matrix;
+
+/**
+ * User: serso
+ * Date: 7/11/13
+ * Time: 4:56 PM
+ */
+public class MatrixViewTest {
+}