diff --git a/src/net/azib/ipscan/gui/AbstractModalDialog.java b/src/net/azib/ipscan/gui/AbstractModalDialog.java
index 2477718d..9f90bbc8 100644
--- a/src/net/azib/ipscan/gui/AbstractModalDialog.java
+++ b/src/net/azib/ipscan/gui/AbstractModalDialog.java
@@ -50,6 +50,13 @@ public abstract class AbstractModalDialog {
 		// forget the reference to the shell (this class is reused in the container)
 		shell = null;
 	}
+
+	protected void close() {
+		if (shell != null && !shell.isDisposed()) {
+			shell.close();
+			shell.dispose();
+		}
+	}
 	
 	/**
 	 * Populates the newly created shell with controls
@@ -141,12 +148,7 @@ public abstract class AbstractModalDialog {
 		Button button = new Button(shell, SWT.NONE);
 		button.setText(Labels.getLabel("button.close"));
 		positionButtons(button, null);
-		
-		button.addListener(SWT.Selection, event -> {
-			shell.close();
-			shell.dispose();
-		});
-		
+		button.addListener(SWT.Selection, event -> close());
 		button.setFocus();
 		return button;
 	}
@@ -154,7 +156,6 @@ public abstract class AbstractModalDialog {
 	// common listeners follow
 	
 	protected static class UpButtonListener implements Listener {
-		
 		private List list;
 
 		public UpButtonListener(List list) {
diff --git a/src/net/azib/ipscan/gui/DetailsWindow.java b/src/net/azib/ipscan/gui/DetailsWindow.java
index 86847e03..f16f756d 100644
--- a/src/net/azib/ipscan/gui/DetailsWindow.java
+++ b/src/net/azib/ipscan/gui/DetailsWindow.java
@@ -109,10 +109,7 @@ public class DetailsWindow extends AbstractModalDialog {
 	
 	class TraverseListener implements Listener {
 		public void handleEvent(Event e) {
-			if (e.detail == SWT.TRAVERSE_RETURN) {
-				shell.close();
-				shell.dispose();
-			}
+			if (e.detail == SWT.TRAVERSE_RETURN) close();
 		}
 	}
 }
diff --git a/src/net/azib/ipscan/gui/EditFavoritesDialog.java b/src/net/azib/ipscan/gui/EditFavoritesDialog.java
index e869d941..6393fc5d 100644
--- a/src/net/azib/ipscan/gui/EditFavoritesDialog.java
+++ b/src/net/azib/ipscan/gui/EditFavoritesDialog.java
@@ -3,7 +3,6 @@ package net.azib.ipscan.gui;
 import net.azib.ipscan.config.FavoritesConfig;
 import net.azib.ipscan.config.Labels;
 import org.eclipse.swt.SWT;
-import org.eclipse.swt.events.SelectionAdapter;
 import org.eclipse.swt.layout.FormAttachment;
 import org.eclipse.swt.widgets.*;
 
@@ -70,17 +69,11 @@ public class EditFavoritesDialog extends AbstractModalDialog {
 		
 		shell.pack();
 		
-		okButton.addSelectionListener(new SelectionAdapter() {
-			public void widgetSelected(org.eclipse.swt.events.SelectionEvent e) {
-				saveFavorites();
-				shell.close();
-			}
-		});
-		cancelButton.addSelectionListener(new SelectionAdapter() {
-			public void widgetSelected(org.eclipse.swt.events.SelectionEvent e) {
-				shell.close();
-			}
+		okButton.addListener(SWT.Selection, e -> {
+			saveFavorites();
+			close();
 		});
+		cancelButton.addListener(SWT.Selection, e -> close());
 	}
 	
 	private void saveFavorites() {
diff --git a/src/net/azib/ipscan/gui/EditOpenersDialog.java b/src/net/azib/ipscan/gui/EditOpenersDialog.java
index f355c6ec..7f743bd1 100644
--- a/src/net/azib/ipscan/gui/EditOpenersDialog.java
+++ b/src/net/azib/ipscan/gui/EditOpenersDialog.java
@@ -7,7 +7,6 @@ import net.azib.ipscan.fetchers.Fetcher;
 import net.azib.ipscan.fetchers.FetcherRegistry;
 import net.azib.ipscan.gui.util.LayoutHelper;
 import org.eclipse.swt.SWT;
-import org.eclipse.swt.events.SelectionAdapter;
 import org.eclipse.swt.graphics.Font;
 import org.eclipse.swt.layout.FormAttachment;
 import org.eclipse.swt.layout.RowLayout;
@@ -141,17 +140,11 @@ public class EditOpenersDialog extends AbstractModalDialog {
 
 		shell.pack();
 
-		okButton.addSelectionListener(new SelectionAdapter() {
-			public void widgetSelected(org.eclipse.swt.events.SelectionEvent e) {
-				saveOpeners();
-				shell.close();
-			}
-		});
-		cancelButton.addSelectionListener(new SelectionAdapter() {
-			public void widgetSelected(org.eclipse.swt.events.SelectionEvent e) {
-				shell.close();
-			}
+		okButton.addListener(SWT.Selection, e -> {
+			saveOpeners();
+			close();
 		});
+		cancelButton.addListener(SWT.Selection, e -> close());
 
 		openersList.select(0);
 		loadFieldsForSelection();
diff --git a/src/net/azib/ipscan/gui/GettingStartedDialog.java b/src/net/azib/ipscan/gui/GettingStartedDialog.java
index acc3ebbb..02dc406b 100644
--- a/src/net/azib/ipscan/gui/GettingStartedDialog.java
+++ b/src/net/azib/ipscan/gui/GettingStartedDialog.java
@@ -78,11 +78,8 @@ public class GettingStartedDialog extends AbstractModalDialog {
 		gettingStartedText.setBounds(leftBound, 10, shell.getClientArea().width - leftBound - 10, closeButton.getLocation().y - 20);
 		gettingStartedText.setBackground(shell.getDisplay().getSystemColor(SWT.COLOR_LIST_BACKGROUND));
 		
-		closeButton.addListener(SWT.Selection, event -> {
-			shell.close();
-			shell.dispose();
-		});
-		nextButton.addListener(SWT.Selection, event -> displayActivePage());
+		closeButton.addListener(SWT.Selection, e -> close());
+		nextButton.addListener(SWT.Selection, e -> displayActivePage());
 
 		displayActivePage();
 	}
diff --git a/src/net/azib/ipscan/gui/PreferencesDialog.java b/src/net/azib/ipscan/gui/PreferencesDialog.java
index f632cad2..ccb7b4ef 100644
--- a/src/net/azib/ipscan/gui/PreferencesDialog.java
+++ b/src/net/azib/ipscan/gui/PreferencesDialog.java
@@ -114,13 +114,15 @@ public class PreferencesDialog extends AbstractModalDialog {
 
 		okButton.addSelectionListener(new SelectionAdapter() {
 			public void widgetSelected(SelectionEvent e) {
-				savePreferences();
-				shell.close();
+				if (shell != null && !shell.isDisposed()) {
+					savePreferences();
+					close();
+				}
 			}
 		});
 		cancelButton.addSelectionListener(new SelectionAdapter() {
 			public void widgetSelected(SelectionEvent e) {
-				shell.close();
+				close();
 			}
 		});
 	}
diff --git a/src/net/azib/ipscan/gui/SelectFetchersDialog.java b/src/net/azib/ipscan/gui/SelectFetchersDialog.java
index cfa0960a..74e19093 100644
--- a/src/net/azib/ipscan/gui/SelectFetchersDialog.java
+++ b/src/net/azib/ipscan/gui/SelectFetchersDialog.java
@@ -136,14 +136,10 @@ public class SelectFetchersDialog extends AbstractModalDialog {
 		
 		shell.pack();
 		
-		cancelButton.addListener(SWT.Selection, e -> {
-			shell.close();
-			shell.dispose();
-		});
+		cancelButton.addListener(SWT.Selection, e -> close());
 		okButton.addListener(SWT.Selection, event -> {
 			saveFetchersToRegistry(selectedFetchersList.getItems());
-			shell.close();
-			shell.dispose();
+			close();
 		});
 	}
 
diff --git a/src/net/azib/ipscan/gui/StatisticsDialog.java b/src/net/azib/ipscan/gui/StatisticsDialog.java
index aa771ebb..7536e580 100644
--- a/src/net/azib/ipscan/gui/StatisticsDialog.java
+++ b/src/net/azib/ipscan/gui/StatisticsDialog.java
@@ -32,13 +32,8 @@ public class StatisticsDialog extends InfoDialog {
 	public void open() {
 		if (scanningResults.isInfoAvailable()) {
 			setMessage(prepareText());
-			
-			if (shell != null) {
-				// close the same window if it is already open ('scanning incomplete')
-				shell.close();
-				shell.dispose();
-			}
-
+			// close the same window if it is already open ('scanning incomplete')
+			if (shell != null) close();
 			super.open();
 		}
 		else {
diff --git a/src/net/azib/ipscan/gui/fetchers/MACFetcherPrefs.java b/src/net/azib/ipscan/gui/fetchers/MACFetcherPrefs.java
index 326645ed..d750a80f 100644
--- a/src/net/azib/ipscan/gui/fetchers/MACFetcherPrefs.java
+++ b/src/net/azib/ipscan/gui/fetchers/MACFetcherPrefs.java
@@ -12,8 +12,6 @@ import net.azib.ipscan.fetchers.MACFetcher;
 import net.azib.ipscan.gui.AbstractModalDialog;
 import net.azib.ipscan.gui.util.LayoutHelper;
 import org.eclipse.swt.SWT;
-import org.eclipse.swt.events.SelectionAdapter;
-import org.eclipse.swt.events.SelectionEvent;
 import org.eclipse.swt.layout.FormAttachment;
 import org.eclipse.swt.widgets.*;
 
@@ -46,17 +44,11 @@ public class MACFetcherPrefs extends AbstractModalDialog implements FetcherPrefs
 
 		positionButtonsInFormLayout(okButton, cancelButton, separator);
 
-		okButton.addSelectionListener(new SelectionAdapter() {
-			public void widgetSelected(SelectionEvent e) {
-				savePreferences();
-				shell.close();
-			}
-		});
-		cancelButton.addSelectionListener(new SelectionAdapter() {
-			public void widgetSelected(SelectionEvent e) {
-				shell.close();
-			}
+		okButton.addListener(SWT.Selection, e -> {
+			savePreferences();
+			close();
 		});
+		cancelButton.addListener(SWT.Selection, e -> close());
 
 		shell.pack();
 	}
diff --git a/src/net/azib/ipscan/gui/fetchers/PortTextFetcherPrefs.java b/src/net/azib/ipscan/gui/fetchers/PortTextFetcherPrefs.java
index 9f6e9286..e23a8247 100644
--- a/src/net/azib/ipscan/gui/fetchers/PortTextFetcherPrefs.java
+++ b/src/net/azib/ipscan/gui/fetchers/PortTextFetcherPrefs.java
@@ -12,8 +12,6 @@ import net.azib.ipscan.fetchers.PortTextFetcher;
 import net.azib.ipscan.gui.AbstractModalDialog;
 import net.azib.ipscan.gui.util.LayoutHelper;
 import org.eclipse.swt.SWT;
-import org.eclipse.swt.events.SelectionAdapter;
-import org.eclipse.swt.events.SelectionEvent;
 import org.eclipse.swt.layout.FormAttachment;
 import org.eclipse.swt.widgets.*;
 
@@ -77,17 +75,11 @@ public class PortTextFetcherPrefs extends AbstractModalDialog implements Fetcher
 
 		positionButtonsInFormLayout(okButton, cancelButton, extractGroup);
 
-		okButton.addSelectionListener(new SelectionAdapter() {
-			public void widgetSelected(SelectionEvent e) {
-				savePreferences();
-				shell.close();
-			}
-		});
-		cancelButton.addSelectionListener(new SelectionAdapter() {
-			public void widgetSelected(SelectionEvent e) {
-				shell.close();
-			}
+		okButton.addListener(SWT.Selection, e -> {
+			savePreferences();
+			close();
 		});
+		cancelButton.addListener(SWT.Selection, e -> close());
 
 		shell.pack();
 	}