diff --git a/jadx-gui/src/main/java/jadx/gui/MainWindow.java b/jadx-gui/src/main/java/jadx/gui/MainWindow.java
index dd16bf19f..447bfdece 100644
--- a/jadx-gui/src/main/java/jadx/gui/MainWindow.java
+++ b/jadx-gui/src/main/java/jadx/gui/MainWindow.java
@@ -6,6 +6,8 @@ import jadx.gui.treemodel.JClass;
 import jadx.gui.treemodel.JNode;
 import jadx.gui.treemodel.JRoot;
 
+import javax.swing.ImageIcon;
+import javax.swing.JButton;
 import javax.swing.JFileChooser;
 import javax.swing.JFrame;
 import javax.swing.JMenu;
@@ -14,6 +16,8 @@ import javax.swing.JMenuItem;
 import javax.swing.JPanel;
 import javax.swing.JScrollPane;
 import javax.swing.JSplitPane;
+import javax.swing.JToggleButton;
+import javax.swing.JToolBar;
 import javax.swing.JTree;
 import javax.swing.event.TreeSelectionEvent;
 import javax.swing.event.TreeSelectionListener;
@@ -22,6 +26,7 @@ import javax.swing.filechooser.FileNameExtensionFilter;
 import javax.swing.tree.DefaultMutableTreeNode;
 import javax.swing.tree.DefaultTreeCellRenderer;
 import javax.swing.tree.DefaultTreeModel;
+import javax.swing.tree.TreePath;
 import javax.swing.tree.TreeSelectionModel;
 import java.awt.BorderLayout;
 import java.awt.Color;
@@ -40,8 +45,12 @@ import org.slf4j.LoggerFactory;
 public class MainWindow extends JFrame {
 	private static final Logger LOG = LoggerFactory.getLogger(MainWindow.class);
 
-	public static final String DEFAULT_TITLE = "jadx-gui";
-	public static final Color BACKGROUND = new Color(0xf7f7f7);
+	private static final String DEFAULT_TITLE = "jadx-gui";
+	private static final Color BACKGROUND = new Color(0xf7f7f7);
+
+	private static final ImageIcon ICON_OPEN = Utils.openIcon("folder");
+	private static final ImageIcon ICON_CLOSE = Utils.openIcon("cross");
+	private static final ImageIcon ICON_FLAT_PKG = Utils.openIcon("empty_logical_package_obj");
 
 	private final JadxWrapper wrapper;
 	private JPanel mainPanel;
@@ -53,46 +62,7 @@ public class MainWindow extends JFrame {
 		this.wrapper = new JadxWrapper(jadxArgs);
 
 		initUI();
-		initMenu();
-	}
-
-	private void initMenu() {
-		JMenuBar menuBar = new JMenuBar();
-
-		JMenu file = new JMenu("File");
-		file.setMnemonic(KeyEvent.VK_F);
-
-		JMenuItem exit = new JMenuItem("Exit", Utils.openIcon("cross"));
-		exit.setMnemonic(KeyEvent.VK_E);
-		exit.setToolTipText("Exit application");
-		exit.addActionListener(new ActionListener() {
-			public void actionPerformed(ActionEvent event) {
-				System.exit(0);
-			}
-		});
-
-		JMenuItem open = new JMenuItem("Open", Utils.openIcon("folder"));
-		open.setMnemonic(KeyEvent.VK_E);
-		open.setToolTipText("Open file");
-		open.addActionListener(new ActionListener() {
-			public void actionPerformed(ActionEvent event) {
-				JFileChooser fileChooser = new JFileChooser();
-				FileFilter filter = new FileNameExtensionFilter("dex files", "dex", "apk", "jar");
-				fileChooser.addChoosableFileFilter(filter);
-				int ret = fileChooser.showDialog(mainPanel, "Open file");
-				if (ret == JFileChooser.APPROVE_OPTION) {
-					File file = fileChooser.getSelectedFile();
-					openFile(file);
-				}
-			}
-		});
-
-		file.add(open);
-		file.addSeparator();
-		file.add(exit);
-
-		menuBar.add(file);
-		setJMenuBar(menuBar);
+		initMenuAndToolbar();
 	}
 
 	public void openFile(File file) {
@@ -106,6 +76,80 @@ public class MainWindow extends JFrame {
 		treeModel.setRoot(treeRoot);
 		treeModel.reload();
 		tree.expandRow(0);
+//		expandTree();
+	}
+
+	private void toggleFlattenPackage() {
+		Object root = treeModel.getRoot();
+		if (root instanceof JRoot) {
+			JRoot treeRoot = (JRoot) root;
+			treeRoot.setFlatPackages(!treeRoot.isFlatPackages());
+			treeModel.reload();
+			tree.expandRow(0);
+		}
+	}
+
+	private void expandTree() {
+		DefaultMutableTreeNode currentNode = ((DefaultMutableTreeNode) tree.getModel().getRoot()).getNextNode();
+		do {
+			if (currentNode.getLevel() == 1) {
+				tree.expandPath(new TreePath(currentNode.getPath()));
+			}
+			currentNode = currentNode.getNextNode();
+		}
+		while (currentNode != null);
+	}
+
+	private void initMenuAndToolbar() {
+		JMenuBar menuBar = new JMenuBar();
+
+		JMenu file = new JMenu("File");
+		file.setMnemonic(KeyEvent.VK_F);
+
+		JMenuItem exit = new JMenuItem("Exit", ICON_CLOSE);
+		exit.setMnemonic(KeyEvent.VK_E);
+		exit.setToolTipText("Exit application");
+		exit.addActionListener(new ActionListener() {
+			public void actionPerformed(ActionEvent event) {
+				System.exit(0);
+			}
+		});
+
+		JMenuItem open = new JMenuItem("Open", ICON_OPEN);
+		open.setMnemonic(KeyEvent.VK_E);
+		open.setToolTipText("Open file");
+		open.addActionListener(new OpenListener());
+
+		file.add(open);
+		file.addSeparator();
+		file.add(exit);
+
+		menuBar.add(file);
+		setJMenuBar(menuBar);
+
+		JToolBar toolbar = new JToolBar();
+		toolbar.setFloatable(false);
+
+		JButton openButton = new JButton(ICON_OPEN);
+		openButton.addActionListener(new OpenListener());
+		openButton.setToolTipText(NLS.str("file.open"));
+
+		toolbar.add(openButton);
+		toolbar.addSeparator();
+
+		JToggleButton flatPkgButton = new JToggleButton(ICON_FLAT_PKG);
+		flatPkgButton.addActionListener(new ActionListener() {
+			@Override
+			public void actionPerformed(ActionEvent e) {
+				toggleFlattenPackage();
+			}
+		});
+		flatPkgButton.setToolTipText(NLS.str("tree.flatten"));
+		toolbar.add(flatPkgButton);
+
+		toolbar.addSeparator();
+
+		add(toolbar, BorderLayout.NORTH);
 	}
 
 	private void initUI() {
@@ -166,4 +210,17 @@ public class MainWindow extends JFrame {
 		pack();
 		setLocationRelativeTo(null);
 	}
+
+	private class OpenListener implements ActionListener {
+		public void actionPerformed(ActionEvent event) {
+			JFileChooser fileChooser = new JFileChooser();
+			FileFilter filter = new FileNameExtensionFilter("dex files", "dex", "apk", "jar");
+			fileChooser.addChoosableFileFilter(filter);
+			int ret = fileChooser.showDialog(mainPanel, "Open file");
+			if (ret == JFileChooser.APPROVE_OPTION) {
+				File file = fileChooser.getSelectedFile();
+				openFile(file);
+			}
+		}
+	}
 }
diff --git a/jadx-gui/src/main/java/jadx/gui/NLS.java b/jadx-gui/src/main/java/jadx/gui/NLS.java
new file mode 100644
index 000000000..c3bf3e2dc
--- /dev/null
+++ b/jadx-gui/src/main/java/jadx/gui/NLS.java
@@ -0,0 +1,21 @@
+package jadx.gui;
+
+import java.util.Locale;
+import java.util.ResourceBundle;
+
+public class NLS {
+
+	private static ResourceBundle messages;
+
+	static {
+		load(new Locale("en", "US"));
+	}
+
+	public static void load(Locale locale) {
+		messages = ResourceBundle.getBundle("i18n/Messages", locale);
+	}
+
+	public static String str(String key) {
+		return messages.getString(key);
+	}
+}
diff --git a/jadx-gui/src/main/java/jadx/gui/treemodel/JClass.java b/jadx-gui/src/main/java/jadx/gui/treemodel/JClass.java
index 252b15b40..fabf948e2 100644
--- a/jadx-gui/src/main/java/jadx/gui/treemodel/JClass.java
+++ b/jadx-gui/src/main/java/jadx/gui/treemodel/JClass.java
@@ -1,26 +1,60 @@
 package jadx.gui.treemodel;
 
 import jadx.api.JavaClass;
+import jadx.core.dex.info.AccessInfo;
 import jadx.gui.Utils;
 
 import javax.swing.Icon;
+import javax.swing.ImageIcon;
 import javax.swing.tree.DefaultMutableTreeNode;
 
 public class JClass extends DefaultMutableTreeNode implements JNode {
 
+	private static final ImageIcon ICON_CLASS = Utils.openIcon("class_obj");
+	private static final ImageIcon ICON_CLASS_DEFAULT = Utils.openIcon("class_default_obj");
+	private static final ImageIcon ICON_CLASS_PRIVATE = Utils.openIcon("innerclass_private_obj");
+	private static final ImageIcon ICON_CLASS_PROTECTED = Utils.openIcon("innerclass_protected_obj");
+	private static final ImageIcon ICON_INTERFACE = Utils.openIcon("int_obj");
+	private static final ImageIcon ICON_ENUM = Utils.openIcon("enum_obj");
+	private static final ImageIcon ICON_ANNOTATION = Utils.openIcon("annotation_obj");
+
 	private final JavaClass cls;
 
 	public JClass(JavaClass cls) {
 		this.cls = cls;
+		updateChilds();
 	}
 
 	public JavaClass getCls() {
 		return cls;
 	}
 
+	@Override
+	public void updateChilds() {
+//		for (JavaClass javaClass : cls.getInnerClasses()) {
+//			add(new JClass(javaClass));
+//		}
+	}
+
 	@Override
 	public Icon getIcon() {
-		return Utils.openIcon("class_obj");
+		AccessInfo accessInfo = cls.getAccessInfo();
+
+		if (accessInfo.isEnum()) {
+			return ICON_ENUM;
+		} else if (accessInfo.isAnnotation()) {
+			return ICON_ANNOTATION;
+		} else if (accessInfo.isInterface()) {
+			return ICON_INTERFACE;
+		} else if (accessInfo.isProtected()) {
+			return ICON_CLASS_PROTECTED;
+		} else if (accessInfo.isPrivate()) {
+			return ICON_CLASS_PRIVATE;
+		} else if (accessInfo.isPublic()) {
+			return ICON_CLASS;
+		} else {
+			return ICON_CLASS_DEFAULT;
+		}
 	}
 
 	@Override
diff --git a/jadx-gui/src/main/java/jadx/gui/treemodel/JNode.java b/jadx-gui/src/main/java/jadx/gui/treemodel/JNode.java
index b05409ed3..45a12aa87 100644
--- a/jadx-gui/src/main/java/jadx/gui/treemodel/JNode.java
+++ b/jadx-gui/src/main/java/jadx/gui/treemodel/JNode.java
@@ -3,5 +3,8 @@ package jadx.gui.treemodel;
 import javax.swing.Icon;
 
 public interface JNode {
+
+	void updateChilds();
+
 	Icon getIcon();
 }
diff --git a/jadx-gui/src/main/java/jadx/gui/treemodel/JPackage.java b/jadx-gui/src/main/java/jadx/gui/treemodel/JPackage.java
index 029c947e2..158f82854 100644
--- a/jadx-gui/src/main/java/jadx/gui/treemodel/JPackage.java
+++ b/jadx-gui/src/main/java/jadx/gui/treemodel/JPackage.java
@@ -7,22 +7,57 @@ import jadx.gui.Utils;
 import javax.swing.Icon;
 import javax.swing.ImageIcon;
 import javax.swing.tree.DefaultMutableTreeNode;
+import java.util.ArrayList;
+import java.util.List;
 
-public class JPackage extends DefaultMutableTreeNode implements JNode {
+public class JPackage extends DefaultMutableTreeNode implements JNode, Comparable<JPackage> {
 	private static final ImageIcon PACKAGE_ICON = Utils.openIcon("package_obj");
 
-	private final JavaPackage pkg;
+	private String name;
+	private List<JClass> classes;
+	private List<JPackage> innerPackages = new ArrayList<JPackage>(1);
 
 	public JPackage(JavaPackage pkg) {
-		this.pkg = pkg;
+		this.name = pkg.getName();
+		List<JavaClass> javaClasses = pkg.getClasses();
+		this.classes = new ArrayList<JClass>(javaClasses.size());
+		for (JavaClass javaClass : javaClasses) {
+			classes.add(new JClass(javaClass));
+		}
+		updateChilds();
+	}
 
-		for (JavaClass javaClass : pkg.getClasses()) {
-			add(new JClass(javaClass));
+	public JPackage(String name) {
+		this.name = name;
+		this.classes = new ArrayList<JClass>(1);
+	}
+
+	@Override
+	public void updateChilds() {
+		removeAllChildren();
+		for (JPackage pkg : innerPackages) {
+			pkg.updateChilds();
+			add(pkg);
+		}
+		for (JClass cls : classes) {
+			add(cls);
 		}
 	}
 
-	public JavaPackage getPkg() {
-		return pkg;
+	public String getName() {
+		return name;
+	}
+
+	public void setName(String name) {
+		this.name = name;
+	}
+
+	public List<JPackage> getInnerPackages() {
+		return innerPackages;
+	}
+
+	public List<JClass> getClasses() {
+		return classes;
 	}
 
 	@Override
@@ -30,8 +65,13 @@ public class JPackage extends DefaultMutableTreeNode implements JNode {
 		return PACKAGE_ICON;
 	}
 
+	@Override
+	public int compareTo(JPackage o) {
+		return name.compareTo(o.name);
+	}
+
 	@Override
 	public String toString() {
-		return pkg.getName();
+		return name;
 	}
 }
diff --git a/jadx-gui/src/main/java/jadx/gui/treemodel/JRoot.java b/jadx-gui/src/main/java/jadx/gui/treemodel/JRoot.java
index dfc755e91..f00cabb72 100644
--- a/jadx-gui/src/main/java/jadx/gui/treemodel/JRoot.java
+++ b/jadx-gui/src/main/java/jadx/gui/treemodel/JRoot.java
@@ -8,6 +8,14 @@ import javax.swing.Icon;
 import javax.swing.ImageIcon;
 import javax.swing.tree.DefaultMutableTreeNode;
 import java.io.File;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
 
 public class JRoot extends DefaultMutableTreeNode implements JNode {
 
@@ -15,11 +23,93 @@ public class JRoot extends DefaultMutableTreeNode implements JNode {
 
 	private final JadxWrapper wrapper;
 
+	private boolean flatPackages = false;
+
 	public JRoot(JadxWrapper wrapper) {
 		this.wrapper = wrapper;
+		updateChilds();
+	}
 
-		for (JavaPackage pkg : wrapper.getPackages()) {
-			add(new JPackage(pkg));
+	@Override
+	public void updateChilds() {
+		removeAllChildren();
+		if (flatPackages) {
+			for (JavaPackage pkg : wrapper.getPackages()) {
+				add(new JPackage(pkg));
+			}
+		} else {
+			// build packages hierarchy
+			Map<String, JPackage> pkgMap = new HashMap<String, JPackage>();
+			for (JavaPackage pkg : wrapper.getPackages()) {
+				addPackage(pkgMap, new JPackage(pkg));
+			}
+			// merge packages without classes
+			for (JPackage pkg : pkgMap.values()) {
+				if (pkg.getInnerPackages().size() == 1 && pkg.getClasses().isEmpty()) {
+					JPackage innerPkg = pkg.getInnerPackages().get(0);
+					pkg.getInnerPackages().clear();
+					pkg.getInnerPackages().addAll(innerPkg.getInnerPackages());
+					pkg.getClasses().addAll(innerPkg.getClasses());
+					pkg.setName(pkg.getName() + "." + innerPkg.getName());
+					innerPkg.getInnerPackages().clear();
+					innerPkg.getClasses().clear();
+				}
+			}
+			// remove empty packages
+			for (Iterator<Map.Entry<String, JPackage>> it = pkgMap.entrySet().iterator(); it.hasNext(); ) {
+				JPackage pkg = it.next().getValue();
+				if (pkg.getInnerPackages().isEmpty() && pkg.getClasses().isEmpty()) {
+					it.remove();
+				}
+			}
+			// find root packages
+			Set<JPackage> inners = new HashSet<JPackage>();
+			for (JPackage pkg : pkgMap.values()) {
+				inners.addAll(pkg.getInnerPackages());
+			}
+			List<JPackage> rootPkgs = new ArrayList<JPackage>();
+			for (JPackage pkg : pkgMap.values()) {
+				if (!inners.contains(pkg)) {
+					rootPkgs.add(pkg);
+				}
+			}
+			Collections.sort(rootPkgs);
+			for (JPackage jPackage : rootPkgs) {
+				jPackage.updateChilds();
+				add(jPackage);
+			}
+		}
+	}
+
+	private void addPackage(Map<String, JPackage> pkgs, JPackage pkg) {
+		String pkgName = pkg.getName();
+		JPackage replaced = pkgs.put(pkgName, pkg);
+		if (replaced != null) {
+			pkg.getInnerPackages().addAll(replaced.getInnerPackages());
+			pkg.getClasses().addAll(replaced.getClasses());
+		}
+		int dot = pkgName.lastIndexOf('.');
+		if (dot > 0) {
+			String prevPart = pkgName.substring(0, dot);
+			String shortName = pkgName.substring(dot + 1);
+			pkg.setName(shortName);
+			JPackage prevPkg = pkgs.get(prevPart);
+			if (prevPkg == null) {
+				prevPkg = new JPackage(prevPart);
+				addPackage(pkgs, prevPkg);
+			}
+			prevPkg.getInnerPackages().add(pkg);
+		}
+	}
+
+	public boolean isFlatPackages() {
+		return flatPackages;
+	}
+
+	public void setFlatPackages(boolean flatPackages) {
+		if (this.flatPackages != flatPackages) {
+			this.flatPackages = flatPackages;
+			updateChilds();
 		}
 	}
 
diff --git a/jadx-gui/src/main/resources/i18n/Messages_en_US.properties b/jadx-gui/src/main/resources/i18n/Messages_en_US.properties
new file mode 100644
index 000000000..2f6124650
--- /dev/null
+++ b/jadx-gui/src/main/resources/i18n/Messages_en_US.properties
@@ -0,0 +1,2 @@
+file.open=Open file
+tree.flatten=Flatten packages
diff --git a/jadx-gui/src/main/resources/icons-16/abstract_co.png b/jadx-gui/src/main/resources/icons-16/abstract_co.png
new file mode 100644
index 000000000..658b8fde5
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diff --git a/jadx-gui/src/main/resources/icons-16/constr_ovr.png b/jadx-gui/src/main/resources/icons-16/constr_ovr.png
new file mode 100644
index 000000000..65964a92e
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diff --git a/jadx-gui/src/main/resources/icons-16/empty_logical_package_obj.png b/jadx-gui/src/main/resources/icons-16/empty_logical_package_obj.png
new file mode 100644
index 000000000..acfb2238a
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diff --git a/jadx-gui/src/main/resources/icons-16/empty_pack_obj.png b/jadx-gui/src/main/resources/icons-16/empty_pack_obj.png
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index 000000000..a2d43103f
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diff --git a/jadx-gui/src/main/resources/icons-16/field_private_obj.png b/jadx-gui/src/main/resources/icons-16/field_private_obj.png
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diff --git a/jadx-gui/src/main/resources/icons-16/field_protected_obj.png b/jadx-gui/src/main/resources/icons-16/field_protected_obj.png
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index 000000000..dc80489bc
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diff --git a/jadx-gui/src/main/resources/icons-16/field_public_obj.png b/jadx-gui/src/main/resources/icons-16/field_public_obj.png
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diff --git a/jadx-gui/src/main/resources/icons-16/final_co.png b/jadx-gui/src/main/resources/icons-16/final_co.png
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diff --git a/jadx-gui/src/main/resources/icons-16/native_co.png b/jadx-gui/src/main/resources/icons-16/native_co.png
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index 000000000..bb410c523
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diff --git a/jadx-gui/src/main/resources/icons-16/run_co.png b/jadx-gui/src/main/resources/icons-16/run_co.png
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diff --git a/jadx-gui/src/main/resources/icons-16/static_co.png b/jadx-gui/src/main/resources/icons-16/static_co.png
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index 000000000..655c9c069
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diff --git a/jadx-gui/src/main/resources/icons-16/synch_co.png b/jadx-gui/src/main/resources/icons-16/synch_co.png
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index 000000000..2e950e988
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diff --git a/jadx-gui/src/main/resources/icons-16/transient_co.png b/jadx-gui/src/main/resources/icons-16/transient_co.png
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index 000000000..4f54e545e
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diff --git a/jadx-gui/src/main/resources/icons-16/volatile_co.png b/jadx-gui/src/main/resources/icons-16/volatile_co.png
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