diff --git a/src/ert/gui/main_window.py b/src/ert/gui/main_window.py
index 273157e8779..97689022c82 100644
--- a/src/ert/gui/main_window.py
+++ b/src/ert/gui/main_window.py
@@ -9,6 +9,7 @@
 from qtpy.QtGui import QCloseEvent, QCursor, QIcon
 from qtpy.QtWidgets import (
     QAction,
+    QButtonGroup,
     QFrame,
     QHBoxLayout,
     QMainWindow,
@@ -50,6 +51,7 @@
     BUTTON_STYLE_SHEET
     + """
     QToolButton:hover {background-color: rgba(50, 50, 50, 90);}
+    QToolButton:checked {background-color: rgba(50, 50, 50, 120);}
     """
 )
 
@@ -57,6 +59,7 @@
     BUTTON_STYLE_SHEET
     + """
     QToolButton:hover {background-color: rgba(30, 30, 30, 150);}
+    QToolButton:checked {background-color: rgba(30, 30, 30, 120);}
     """
 )
 
@@ -87,6 +90,7 @@ def __init__(
         self.central_widget.setLayout(self.central_layout)
         self.facade = LibresFacade(self.ert_config)
         self.side_frame = QFrame(self)
+        self.button_group = QButtonGroup(self.side_frame)
 
         if self.is_dark_mode():
             self.side_frame.setStyleSheet("background-color: rgb(64, 64, 64);")
@@ -233,6 +237,7 @@ def post_init(self) -> None:
 
     def _add_sidebar_button(self, name: str, icon: QIcon) -> QToolButton:
         button = QToolButton(self.side_frame)
+        button.setCheckable(True)
         button.setFixedSize(85, 95)
         button.setCursor(QCursor(Qt.CursorShape.PointingHandCursor))
 
@@ -254,6 +259,7 @@ def _add_sidebar_button(self, name: str, icon: QIcon) -> QToolButton:
 
         button.clicked.connect(self.select_central_widget)
         button.setProperty("index", name)
+        self.button_group.addButton(button)
         return button
 
     def __add_help_menu(self) -> None: