diff --git a/FSL/src/fsl_mainwindow.cpp b/FSL/src/fsl_mainwindow.cpp
index cb463517100bfb44f5171ccb30ea7b0571fcc88e..2c4cfe9952bbbefac6530778e7268f63ddfed69a 100644
--- a/FSL/src/fsl_mainwindow.cpp
+++ b/FSL/src/fsl_mainwindow.cpp
@@ -761,6 +761,24 @@ void FSLMainWindow::configure_generator()
         p_z = 0;
 
     }
+    else if(generator=="User Primary Generator")
+    {
+        ui->pB_pythia_browse->setEnabled(false);
+        ui->cB_pythia_type_of_eve->setEnabled(false);
+        ui->cB_particle->setEnabled(false);
+        ui->lE_px->setEnabled(false);
+        ui->lE_py->setEnabled(false);
+        ui->lE_pz->setEnabled(false);
+
+        pythia_type_of_event = "";
+        pythia_input_file = "";
+        particle = "";
+        particle_energy = "";
+        particle_direction = "";
+        p_x = 0;
+        p_y = 0;
+        p_z = 0;
+    }
 
 }
 
diff --git a/FSL/src/fsl_mainwindow.ui b/FSL/src/fsl_mainwindow.ui
index cdfe65a92fbf2fa200996073a66a4fbe6c09ad26..8d4c9dbdb4771223c76258d3b7ae2406c02ab333 100644
--- a/FSL/src/fsl_mainwindow.ui
+++ b/FSL/src/fsl_mainwindow.ui
@@ -6,7 +6,7 @@
    <rect>
     <x>0</x>
     <y>0</y>
-    <width>1261</width>
+    <width>1291</width>
     <height>726</height>
    </rect>
   </property>
@@ -241,76 +241,6 @@
           </property>
          </widget>
         </item>
-        <item row="0" column="3">
-         <spacer name="verticalSpacer_9">
-          <property name="orientation">
-           <enum>Qt::Vertical</enum>
-          </property>
-          <property name="sizeHint" stdset="0">
-           <size>
-            <width>20</width>
-            <height>76</height>
-           </size>
-          </property>
-         </spacer>
-        </item>
-        <item row="1" column="1" colspan="2">
-         <spacer name="horizontalSpacer_21">
-          <property name="orientation">
-           <enum>Qt::Horizontal</enum>
-          </property>
-          <property name="sizeHint" stdset="0">
-           <size>
-            <width>383</width>
-            <height>20</height>
-           </size>
-          </property>
-         </spacer>
-        </item>
-        <item row="1" column="4">
-         <widget class="QGroupBox" name="groupBox_2">
-          <property name="font">
-           <font>
-            <pointsize>15</pointsize>
-           </font>
-          </property>
-          <property name="title">
-           <string>Select Generator</string>
-          </property>
-          <layout class="QHBoxLayout" name="horizontalLayout_11">
-           <item>
-            <widget class="QComboBox" name="cB_gen_options">
-             <property name="currentText">
-              <string>Particle Gun</string>
-             </property>
-             <item>
-              <property name="text">
-               <string>Particle Gun</string>
-              </property>
-             </item>
-             <item>
-              <property name="text">
-               <string>Pythia</string>
-              </property>
-             </item>
-            </widget>
-           </item>
-          </layout>
-         </widget>
-        </item>
-        <item row="1" column="5">
-         <spacer name="horizontalSpacer_22">
-          <property name="orientation">
-           <enum>Qt::Horizontal</enum>
-          </property>
-          <property name="sizeHint" stdset="0">
-           <size>
-            <width>308</width>
-            <height>20</height>
-           </size>
-          </property>
-         </spacer>
-        </item>
         <item row="2" column="2" rowspan="2">
          <widget class="QGroupBox" name="groupBox_4">
           <property name="font">
@@ -472,27 +402,53 @@
           </layout>
          </widget>
         </item>
-        <item row="2" column="3">
-         <spacer name="verticalSpacer_3">
+        <item row="3" column="0" colspan="2">
+         <spacer name="horizontalSpacer_4">
+          <property name="orientation">
+           <enum>Qt::Horizontal</enum>
+          </property>
+          <property name="sizeHint" stdset="0">
+           <size>
+            <width>122</width>
+            <height>20</height>
+           </size>
+          </property>
+         </spacer>
+        </item>
+        <item row="0" column="3">
+         <spacer name="verticalSpacer_9">
           <property name="orientation">
            <enum>Qt::Vertical</enum>
           </property>
           <property name="sizeHint" stdset="0">
            <size>
             <width>20</width>
-            <height>137</height>
+            <height>76</height>
            </size>
           </property>
          </spacer>
         </item>
-        <item row="3" column="0" colspan="2">
-         <spacer name="horizontalSpacer_4">
+        <item row="5" column="2">
+         <spacer name="verticalSpacer_10">
+          <property name="orientation">
+           <enum>Qt::Vertical</enum>
+          </property>
+          <property name="sizeHint" stdset="0">
+           <size>
+            <width>20</width>
+            <height>32</height>
+           </size>
+          </property>
+         </spacer>
+        </item>
+        <item row="1" column="5">
+         <spacer name="horizontalSpacer_22">
           <property name="orientation">
            <enum>Qt::Horizontal</enum>
           </property>
           <property name="sizeHint" stdset="0">
            <size>
-            <width>122</width>
+            <width>308</width>
             <height>20</height>
            </size>
           </property>
@@ -593,15 +549,28 @@
           </property>
          </spacer>
         </item>
-        <item row="5" column="2">
-         <spacer name="verticalSpacer_10">
+        <item row="2" column="3">
+         <spacer name="verticalSpacer_3">
           <property name="orientation">
            <enum>Qt::Vertical</enum>
           </property>
           <property name="sizeHint" stdset="0">
            <size>
             <width>20</width>
-            <height>32</height>
+            <height>137</height>
+           </size>
+          </property>
+         </spacer>
+        </item>
+        <item row="1" column="1" colspan="2">
+         <spacer name="horizontalSpacer_21">
+          <property name="orientation">
+           <enum>Qt::Horizontal</enum>
+          </property>
+          <property name="sizeHint" stdset="0">
+           <size>
+            <width>383</width>
+            <height>20</height>
            </size>
           </property>
          </spacer>
@@ -619,6 +588,42 @@
           </property>
          </spacer>
         </item>
+        <item row="1" column="4">
+         <widget class="QGroupBox" name="groupBox_2">
+          <property name="font">
+           <font>
+            <pointsize>15</pointsize>
+           </font>
+          </property>
+          <property name="title">
+           <string>Select Generator</string>
+          </property>
+          <layout class="QHBoxLayout" name="horizontalLayout_11">
+           <item>
+            <widget class="QComboBox" name="cB_gen_options">
+             <property name="currentText">
+              <string>Particle Gun</string>
+             </property>
+             <item>
+              <property name="text">
+               <string>Particle Gun</string>
+              </property>
+             </item>
+             <item>
+              <property name="text">
+               <string>User Primary Generator</string>
+              </property>
+             </item>
+             <item>
+              <property name="text">
+               <string>Pythia</string>
+              </property>
+             </item>
+            </widget>
+           </item>
+          </layout>
+         </widget>
+        </item>
        </layout>
       </widget>
       <widget class="QWidget" name="G4UI">
@@ -1362,8 +1367,8 @@
     <rect>
      <x>0</x>
      <y>0</y>
-     <width>1261</width>
-     <height>24</height>
+     <width>1291</width>
+     <height>20</height>
     </rect>
    </property>
    <widget class="QMenu" name="menuFile">