diff --git a/src/opensesim/gui/PreferencesEditor/EditPreferencesDialog.form b/src/opensesim/gui/PreferencesEditor/EditPreferencesDialog.form
index af27bbe..c0e3bd4 100644
--- a/src/opensesim/gui/PreferencesEditor/EditPreferencesDialog.form
+++ b/src/opensesim/gui/PreferencesEditor/EditPreferencesDialog.form
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8" ?>
 
-<Form version="1.3" maxVersion="1.9" type="org.netbeans.modules.form.forminfo.JDialogFormInfo">
+<Form version="1.5" maxVersion="1.9" type="org.netbeans.modules.form.forminfo.JDialogFormInfo">
   <Properties>
     <Property name="defaultCloseOperation" type="int" value="2"/>
     <Property name="title" type="java.lang.String" value="OpenSeSim Preferences"/>
@@ -30,22 +30,10 @@
           <Group type="102" attributes="0">
               <EmptySpace max="-2" attributes="0"/>
               <Group type="103" groupAlignment="0" attributes="0">
-                  <Group type="102" alignment="0" attributes="0">
-                      <Component id="jLabel1" min="-2" pref="100" max="-2" attributes="0"/>
-                      <EmptySpace min="-2" pref="28" max="-2" attributes="0"/>
-                      <Component id="lafComboBox" max="32767" attributes="0"/>
-                  </Group>
                   <Group type="102" alignment="1" attributes="0">
                       <Component id="jLabel2" max="32767" attributes="0"/>
                       <EmptySpace min="-2" pref="418" max="-2" attributes="0"/>
                   </Group>
-                  <Group type="102" attributes="0">
-                      <Group type="103" groupAlignment="0" attributes="0">
-                          <Component id="godmodeCheckBox" min="-2" max="-2" attributes="0"/>
-                          <Component id="jDevleopmentFeaturesCheckBox" alignment="0" min="-2" max="-2" attributes="0"/>
-                      </Group>
-                      <EmptySpace min="0" pref="0" max="32767" attributes="0"/>
-                  </Group>
                   <Group type="102" alignment="1" attributes="0">
                       <Group type="103" groupAlignment="0" attributes="0">
                           <Group type="102" attributes="0">
@@ -64,8 +52,25 @@
                       </Group>
                       <EmptySpace min="-2" pref="3" max="-2" attributes="0"/>
                   </Group>
+                  <Group type="102" attributes="0">
+                      <Group type="103" groupAlignment="0" attributes="0">
+                          <Component id="godmodeCheckBox" min="-2" max="-2" attributes="0"/>
+                          <Component id="jDevleopmentFeaturesCheckBox" alignment="0" min="-2" max="-2" attributes="0"/>
+                          <Group type="102" alignment="0" attributes="0">
+                              <Component id="jLabel3" min="-2" max="-2" attributes="0"/>
+                              <EmptySpace max="-2" attributes="0"/>
+                              <Component id="jSpinner1" min="-2" pref="51" max="-2" attributes="0"/>
+                          </Group>
+                      </Group>
+                      <EmptySpace min="0" pref="0" max="32767" attributes="0"/>
+                  </Group>
+                  <Group type="102" alignment="0" attributes="0">
+                      <Component id="jLabel1" min="-2" pref="127" max="-2" attributes="0"/>
+                      <EmptySpace max="-2" attributes="0"/>
+                      <Component id="lafComboBox" max="32767" attributes="0"/>
+                  </Group>
               </Group>
-              <EmptySpace min="-2" max="-2" attributes="0"/>
+              <EmptySpace max="-2" attributes="0"/>
           </Group>
       </Group>
     </DimensionLayout>
@@ -90,7 +95,12 @@
                           <Component id="classPathChoseButton" alignment="3" min="-2" max="-2" attributes="0"/>
                           <Component id="xClassPath" alignment="3" min="-2" max="-2" attributes="0"/>
                       </Group>
-                      <EmptySpace pref="68" max="32767" attributes="0"/>
+                      <EmptySpace max="-2" attributes="0"/>
+                      <Group type="103" groupAlignment="0" attributes="0">
+                          <Component id="jSpinner1" min="-2" max="-2" attributes="0"/>
+                          <Component id="jLabel3" min="-2" max="-2" attributes="0"/>
+                      </Group>
+                      <EmptySpace pref="42" max="32767" attributes="0"/>
                   </Group>
                   <Group type="102" alignment="1" attributes="0">
                       <EmptySpace max="32767" attributes="0"/>
@@ -182,5 +192,17 @@
     </Component>
     <Component class="javax.swing.JTextField" name="xClassPath">
     </Component>
+    <Component class="javax.swing.JSpinner" name="jSpinner1">
+      <Properties>
+        <Property name="model" type="javax.swing.SpinnerModel" editor="org.netbeans.modules.form.editors2.SpinnerModelEditor">
+          <SpinnerModel initial="1" minimum="1" numberType="java.lang.Integer" stepSize="1" type="number"/>
+        </Property>
+      </Properties>
+    </Component>
+    <Component class="javax.swing.JLabel" name="jLabel3">
+      <Properties>
+        <Property name="text" type="java.lang.String" value="Number of threads:"/>
+      </Properties>
+    </Component>
   </SubComponents>
 </Form>
diff --git a/src/opensesim/gui/PreferencesEditor/EditPreferencesDialog.java b/src/opensesim/gui/PreferencesEditor/EditPreferencesDialog.java
index 5930907..691f748 100644
--- a/src/opensesim/gui/PreferencesEditor/EditPreferencesDialog.java
+++ b/src/opensesim/gui/PreferencesEditor/EditPreferencesDialog.java
@@ -97,6 +97,8 @@ public class EditPreferencesDialog extends opensesim.gui.util.EscDialog {
         classPathChoseButton = new javax.swing.JButton();
         jLabel2 = new javax.swing.JLabel();
         xClassPath = new javax.swing.JTextField();
+        jSpinner1 = new javax.swing.JSpinner();
+        jLabel3 = new javax.swing.JLabel();
 
         setDefaultCloseOperation(javax.swing.WindowConstants.DISPOSE_ON_CLOSE);
         setTitle("OpenSeSim Preferences");
@@ -148,6 +150,10 @@ public class EditPreferencesDialog extends opensesim.gui.util.EscDialog {
 
         jLabel2.setText("Additional Path:");
 
+        jSpinner1.setModel(new javax.swing.SpinnerNumberModel(1, 1, null, 1));
+
+        jLabel3.setText("Number of threads:");
+
         javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
         getContentPane().setLayout(layout);
         layout.setHorizontalGroup(
@@ -155,18 +161,9 @@ public class EditPreferencesDialog extends opensesim.gui.util.EscDialog {
             .addGroup(layout.createSequentialGroup()
                 .addContainerGap()
                 .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
-                    .addGroup(layout.createSequentialGroup()
-                        .addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 100, javax.swing.GroupLayout.PREFERRED_SIZE)
-                        .addGap(28, 28, 28)
-                        .addComponent(lafComboBox, 0, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
                     .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                         .addComponent(jLabel2, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                         .addGap(418, 418, 418))
-                    .addGroup(layout.createSequentialGroup()
-                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
-                            .addComponent(godmodeCheckBox)
-                            .addComponent(jDevleopmentFeaturesCheckBox))
-                        .addGap(0, 0, Short.MAX_VALUE))
                     .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                         .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                             .addGroup(layout.createSequentialGroup()
@@ -180,7 +177,20 @@ public class EditPreferencesDialog extends opensesim.gui.util.EscDialog {
                                 .addComponent(xClassPath)
                                 .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                                 .addComponent(classPathChoseButton, javax.swing.GroupLayout.PREFERRED_SIZE, 124, javax.swing.GroupLayout.PREFERRED_SIZE)))
-                        .addGap(3, 3, 3)))
+                        .addGap(3, 3, 3))
+                    .addGroup(layout.createSequentialGroup()
+                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
+                            .addComponent(godmodeCheckBox)
+                            .addComponent(jDevleopmentFeaturesCheckBox)
+                            .addGroup(layout.createSequentialGroup()
+                                .addComponent(jLabel3)
+                                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
+                                .addComponent(jSpinner1, javax.swing.GroupLayout.PREFERRED_SIZE, 51, javax.swing.GroupLayout.PREFERRED_SIZE)))
+                        .addGap(0, 0, Short.MAX_VALUE))
+                    .addGroup(layout.createSequentialGroup()
+                        .addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 127, javax.swing.GroupLayout.PREFERRED_SIZE)
+                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
+                        .addComponent(lafComboBox, 0, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)))
                 .addContainerGap())
         );
         layout.setVerticalGroup(
@@ -202,7 +212,11 @@ public class EditPreferencesDialog extends opensesim.gui.util.EscDialog {
                         .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                             .addComponent(classPathChoseButton)
                             .addComponent(xClassPath, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
-                        .addContainerGap(68, Short.MAX_VALUE))
+                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
+                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
+                            .addComponent(jSpinner1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
+                            .addComponent(jLabel3))
+                        .addContainerGap(42, Short.MAX_VALUE))
                     .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                         .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                         .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
@@ -350,6 +364,8 @@ public class EditPreferencesDialog extends opensesim.gui.util.EscDialog {
     private javax.swing.JCheckBox jDevleopmentFeaturesCheckBox;
     private javax.swing.JLabel jLabel1;
     private javax.swing.JLabel jLabel2;
+    private javax.swing.JLabel jLabel3;
+    private javax.swing.JSpinner jSpinner1;
     private javax.swing.JComboBox<String> lafComboBox;
     private javax.swing.JButton okButton;
     private javax.swing.JTextField xClassPath;