diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8b539484205..61cf25bc5be 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -46,6 +46,7 @@ We refer to [GitHub issues](https://github.com/JabRef/jabref/issues) by using `#
 - We fixed an issue where the custom file column were sorted incorrectly. https://github.com/JabRef/jabref/issues/3119
 - We fixed an issues where the entry losses focus when a field is edited and at the same time used for sorting. https://github.com/JabRef/jabref/issues/3373
 - We fixed an issue where the menu on Mac OS was not displayed in the usual Mac-specific way. https://github.com/JabRef/jabref/issues/3146
+- We fixed an issue where the order of fields in customized entry types was not saved correctly. [#4033](http://github.com/JabRef/jabref/issues/4033)
 - We fixed an issue where the groups tree of the last database was still shown even after the database was already closed.
 - We fixed an issue where the "Open file dialog" may disappear behind other windows. https://github.com/JabRef/jabref/issues/3410
 - We fixed an issue where the default icon of a group was not colored correctly.
diff --git a/src/main/java/org/jabref/gui/actions/CustomizeEntryAction.java b/src/main/java/org/jabref/gui/actions/CustomizeEntryAction.java
index aaee283cde1..b8ea7ee567b 100644
--- a/src/main/java/org/jabref/gui/actions/CustomizeEntryAction.java
+++ b/src/main/java/org/jabref/gui/actions/CustomizeEntryAction.java
@@ -3,7 +3,7 @@
 import javax.swing.JDialog;
 
 import org.jabref.gui.JabRefFrame;
-import org.jabref.gui.customentrytypes.EntryCustomizationDialog;
+import org.jabref.gui.customentrytypes.EntryTypeCustomizationDialog;
 
 public class CustomizeEntryAction extends SimpleCommand {
 
@@ -12,10 +12,10 @@ public class CustomizeEntryAction extends SimpleCommand {
     public CustomizeEntryAction(JabRefFrame frame) {
         this.frame = frame;
     }
-    
+
     @Override
     public void execute() {
-        JDialog dialog = new EntryCustomizationDialog(frame);
+        JDialog dialog = new EntryTypeCustomizationDialog(frame);
         dialog.setVisible(true);
     }
 }
diff --git a/src/main/java/org/jabref/gui/customentrytypes/EntryCustomizationDialog.java b/src/main/java/org/jabref/gui/customentrytypes/EntryTypeCustomizationDialog.java
similarity index 95%
rename from src/main/java/org/jabref/gui/customentrytypes/EntryCustomizationDialog.java
rename to src/main/java/org/jabref/gui/customentrytypes/EntryTypeCustomizationDialog.java
index 9c7e8375f60..a9dc764366c 100644
--- a/src/main/java/org/jabref/gui/customentrytypes/EntryCustomizationDialog.java
+++ b/src/main/java/org/jabref/gui/customentrytypes/EntryTypeCustomizationDialog.java
@@ -8,6 +8,7 @@
 import java.awt.event.ActionEvent;
 import java.awt.event.ActionListener;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -49,7 +50,7 @@
 
 import com.jgoodies.forms.builder.ButtonBarBuilder;
 
-public class EntryCustomizationDialog extends JabRefDialog implements ListSelectionListener {
+public class EntryTypeCustomizationDialog extends JabRefDialog implements ListSelectionListener {
 
     protected GridBagLayout gbl = new GridBagLayout();
     protected GridBagConstraints con = new GridBagConstraints();
@@ -71,10 +72,10 @@ public class EntryCustomizationDialog extends JabRefDialog implements ListSelect
     private BibDatabaseMode bibDatabaseMode;
 
     /**
-     * Creates a new instance of EntryCustomizationDialog
+     * Creates a new instance of EntryTypeCustomizationDialog
      */
-    public EntryCustomizationDialog(JabRefFrame frame) {
-        super((JFrame) null, Localization.lang("Customize entry types"), false, EntryCustomizationDialog.class);
+    public EntryTypeCustomizationDialog(JabRefFrame frame) {
+        super((JFrame) null, Localization.lang("Customize entry types"), false, EntryTypeCustomizationDialog.class);
 
         this.frame = frame;
         initGui();
@@ -276,11 +277,13 @@ private void applyChanges() {
                 if (biblatexMode) {
                     Set<String> oldPrimaryOptionalFieldsLists = oldType.get().getPrimaryOptionalFields();
                     Set<String> oldSecondaryOptionalFieldsList = oldType.get().getSecondaryOptionalFields();
-                    if (oldRequiredFieldsList.equals(requiredFieldsList) && oldPrimaryOptionalFieldsLists.equals(optionalFieldsList) &&
-                            oldSecondaryOptionalFieldsList.equals(secondaryOptionalFieldsLists)) {
+                    if (Arrays.equals(oldRequiredFieldsList.toArray(), requiredFieldsList.toArray())
+                            && Arrays.equals(oldPrimaryOptionalFieldsLists.toArray(), optionalFieldsList.toArray())
+                            && Arrays.equals(oldSecondaryOptionalFieldsList.toArray(), secondaryOptionalFieldsLists.toArray())) {
                         changesMade = false;
                     }
-                } else if (oldRequiredFieldsList.equals(requiredFieldsList) && oldOptionalFieldsList.equals(optionalFieldsList)) {
+                } else if (Arrays.equals(oldRequiredFieldsList.toArray(), requiredFieldsList.toArray())
+                        && Arrays.equals(oldOptionalFieldsList.toArray(), optionalFieldsList.toArray())) {
                     changesMade = false;
                 }
             }
diff --git a/src/main/java/org/jabref/gui/customentrytypes/EntryTypeList.java b/src/main/java/org/jabref/gui/customentrytypes/EntryTypeList.java
index 2b6e9c7dc7d..af58aef738b 100644
--- a/src/main/java/org/jabref/gui/customentrytypes/EntryTypeList.java
+++ b/src/main/java/org/jabref/gui/customentrytypes/EntryTypeList.java
@@ -22,7 +22,7 @@
 
 /**
  * This class extends FieldSetComponent to provide some required functionality for the
- * list of entry types in EntryCustomizationDialog.
+ * list of entry types in EntryTypeCustomizationDialog.
  */
 public class EntryTypeList extends FieldSetComponent implements ListSelectionListener {