diff --git a/dfall_ws/src/dfall_pkg/GUI_Qt/flyingAgentGUI/include/controllertabs.h b/dfall_ws/src/dfall_pkg/GUI_Qt/flyingAgentGUI/include/controllertabs.h
index 09c828d17c9d0eb75f98c8411fa3f2065505fc24..ea1ba09875bd8d3b8a591474e555731620b03bbf 100644
--- a/dfall_ws/src/dfall_pkg/GUI_Qt/flyingAgentGUI/include/controllertabs.h
+++ b/dfall_ws/src/dfall_pkg/GUI_Qt/flyingAgentGUI/include/controllertabs.h
@@ -138,10 +138,6 @@ private:
     bool m_should_search_pose_data_for_object_name = false;
     QMutex m_should_search_pose_data_for_object_name_mutex;
 
-    // The color for normal and highlighted tabs
-    QColor m_tab_text_colour_normal;
-    QColor m_tab_text_colour_highlight;
-
     // Mutex for the highlighting of the active controller
     QMutex m_change_highlighted_controller_mutex;
 
diff --git a/dfall_ws/src/dfall_pkg/GUI_Qt/flyingAgentGUI/src/controllertabs.cpp b/dfall_ws/src/dfall_pkg/GUI_Qt/flyingAgentGUI/src/controllertabs.cpp
index 2c873aa4ca2e562ad92977010e2a16fe59c2b64c..485e9ef6ea70b828dda84b4906aa83951c9245a3 100644
--- a/dfall_ws/src/dfall_pkg/GUI_Qt/flyingAgentGUI/src/controllertabs.cpp
+++ b/dfall_ws/src/dfall_pkg/GUI_Qt/flyingAgentGUI/src/controllertabs.cpp
@@ -44,10 +44,6 @@ ControllerTabs::ControllerTabs(QWidget *parent) :
     ui->setupUi(this);
 
 
-    // Specify the color for normal and highlighted tabs
-    m_tab_text_colour_normal = Qt::black;
-    m_tab_text_colour_highlight = QColor(40,120,40);
-
     // Set all the frame to be the inactive colouring
     setAllFramesToControllerIsOffColouring();
 
@@ -440,6 +436,8 @@ void ControllerTabs::controllerUsedChangedCallback(const std_msgs::Int32& msg)
 
 void ControllerTabs::setControllerEnabled(int new_controller)
 {
+    // Define the tab text highlight colour locally
+    const static QColor tab_text_colour_highlight = QColor(40,120,40);
     // Define the on string and style sheet setting locally
     const static QString style_sheet_string_for_on  = "background-color:rgb(40,120,40);";
     const static QString text_for_controller_isOn = "A\nC\nT\nI\nV\nE";
@@ -457,7 +455,7 @@ void ControllerTabs::setControllerEnabled(int new_controller)
     {
        case DEFAULT_CONTROLLER:
        {
-           setTextColourOfTabLabel( m_tab_text_colour_highlight , ui->default_tab );
+           setTextColourOfTabLabel( tab_text_colour_highlight , ui->default_tab );
            ui->frame_isCurrentController_default->setStyleSheet(style_sheet_string_for_on);
            ui->label_isCurrentController_default->setText(text_for_controller_isOn);
            break;
@@ -469,7 +467,7 @@ void ControllerTabs::setControllerEnabled(int new_controller)
         }
         case STUDENT_CONTROLLER:
         {
-            setTextColourOfTabLabel( m_tab_text_colour_highlight , ui->student_tab );
+            setTextColourOfTabLabel( tab_text_colour_highlight , ui->student_tab );
             ui->frame_isCurrentController_student->setStyleSheet(style_sheet_string_for_on);
             ui->label_isCurrentController_student->setText(text_for_controller_isOn);
             break;
@@ -481,35 +479,35 @@ void ControllerTabs::setControllerEnabled(int new_controller)
         }
         case REMOTE_CONTROLLER:
         {
-            setTextColourOfTabLabel( m_tab_text_colour_highlight , ui->remote_tab );
+            setTextColourOfTabLabel( tab_text_colour_highlight , ui->remote_tab );
             ui->frame_isCurrentController_remote->setStyleSheet(style_sheet_string_for_on);
             ui->label_isCurrentController_remote->setText(text_for_controller_isOn);
             break;
         }
         case TUNING_CONTROLLER:
         {
-            setTextColourOfTabLabel( m_tab_text_colour_highlight , ui->tuning_tab );
+            setTextColourOfTabLabel( tab_text_colour_highlight , ui->tuning_tab );
             ui->frame_isCurrentController_tuning->setStyleSheet(style_sheet_string_for_on);
             ui->label_isCurrentController_tuning->setText(text_for_controller_isOn);
             break;
         }
         case PICKER_CONTROLLER:
         {
-            setTextColourOfTabLabel( m_tab_text_colour_highlight , ui->picker_tab );
+            setTextColourOfTabLabel( tab_text_colour_highlight , ui->picker_tab );
             ui->frame_isCurrentController_picker->setStyleSheet(style_sheet_string_for_on);
             ui->label_isCurrentController_picker->setText(text_for_controller_isOn);
             break;
         }
         case TEMPLATE_CONTROLLER:
         {
-            setTextColourOfTabLabel( m_tab_text_colour_highlight , ui->template_tab );
+            setTextColourOfTabLabel( tab_text_colour_highlight , ui->template_tab );
             ui->frame_isCurrentController_template->setStyleSheet(style_sheet_string_for_on);
             ui->label_isCurrentController_template->setText(text_for_controller_isOn);
             break;
         }
         case CSONE_CONTROLLER:
         {
-            setTextColourOfTabLabel( m_tab_text_colour_highlight , ui->csone_tab );
+            setTextColourOfTabLabel( tab_text_colour_highlight , ui->csone_tab );
             ui->frame_isCurrentController_csone->setStyleSheet(style_sheet_string_for_on);
             ui->label_isCurrentController_csone->setText(text_for_controller_isOn);
             break;
@@ -540,17 +538,20 @@ void ControllerTabs::setTextColourOfTabLabel(QColor color , QWidget * tab_widget
 
 void ControllerTabs::setAllTabLabelsToNormalColouring()
 {
+    // Define the tab text normal colour locally
+    const static QColor tab_text_colour_normal = Qt::black;
+
     // Lock the mutex
     m_change_highlighted_controller_mutex.lock();
 
     // Set all the colours to normal
-    setTextColourOfTabLabel( m_tab_text_colour_normal , ui->default_tab );
-    setTextColourOfTabLabel( m_tab_text_colour_normal , ui->student_tab );
-    setTextColourOfTabLabel( m_tab_text_colour_normal , ui->picker_tab );
-    setTextColourOfTabLabel( m_tab_text_colour_normal , ui->tuning_tab );
-    setTextColourOfTabLabel( m_tab_text_colour_normal , ui->remote_tab );
-    setTextColourOfTabLabel( m_tab_text_colour_normal , ui->template_tab );
-    setTextColourOfTabLabel( m_tab_text_colour_normal , ui->csone_tab );
+    setTextColourOfTabLabel( tab_text_colour_normal , ui->default_tab );
+    setTextColourOfTabLabel( tab_text_colour_normal , ui->student_tab );
+    setTextColourOfTabLabel( tab_text_colour_normal , ui->picker_tab );
+    setTextColourOfTabLabel( tab_text_colour_normal , ui->tuning_tab );
+    setTextColourOfTabLabel( tab_text_colour_normal , ui->remote_tab );
+    setTextColourOfTabLabel( tab_text_colour_normal , ui->template_tab );
+    setTextColourOfTabLabel( tab_text_colour_normal , ui->csone_tab );
 
     // Unlock the mutex
     m_change_highlighted_controller_mutex.unlock();
@@ -684,12 +685,16 @@ void ControllerTabs::setAgentIDsToCoordinate(QVector<int> agentIDs , bool should
 
         // SUBSCRIBERS
         // > For receiving message that the instant controller was changed
+        m_change_highlighted_controller_mutex.lock();
         controllerUsedSubscriber = agent_base_nodeHandle.subscribe("FlyingAgentClient/ControllerUsed", 1, &ControllerTabs::controllerUsedChangedCallback, this);
+        m_change_highlighted_controller_mutex.unlock();
     }
     else
     {
         // Unsubscribe
+        m_change_highlighted_controller_mutex.lock();
         controllerUsedSubscriber.shutdown();
+        m_change_highlighted_controller_mutex.unlock();
 
         // Set all tabs to be normal colours
         setAllTabLabelsToNormalColouring();