diff --git a/src/TerminalDisplay.h b/src/TerminalDisplay.h
--- a/src/TerminalDisplay.h
+++ b/src/TerminalDisplay.h
@@ -1037,11 +1037,6 @@
 
     SessionController *_sessionController;
 
-    // Returns true if the screen buffer used in the current session is
-    // the primary/normal buffer or false if it's the alternate/secondary
-    // one
-    bool sessionIsPrimaryScreen();
-
     bool _trimLeadingSpaces;   // trim leading spaces in selected text
     bool _trimTrailingSpaces;   // trim trailing spaces in selected text
     bool _mouseWheelZoom;   // enable mouse wheel zooming or not
diff --git a/src/TerminalDisplay.cpp b/src/TerminalDisplay.cpp
--- a/src/TerminalDisplay.cpp
+++ b/src/TerminalDisplay.cpp
@@ -795,15 +795,16 @@
 }
 void TerminalDisplay::resetCursorStyle()
 {
-    if (sessionController() != nullptr) {
-        Profile::Ptr currentProfile = SessionManager::instance()->sessionProfile(sessionController()->session());
+    Q_ASSERT(_sessionController == nullptr);
+    Q_ASSERT(_sessionController->session() == nullptr);
 
-        if (currentProfile != nullptr) {
-            Enum::CursorShapeEnum shape = static_cast<Enum::CursorShapeEnum>(currentProfile->property<int>(Profile::CursorShape));
+    Profile::Ptr currentProfile = SessionManager::instance()->sessionProfile(_sessionController->session());
 
-            setKeyboardCursorShape(shape);
-            setBlinkingCursorEnabled(currentProfile->blinkingCursorEnabled());
-        }
+    if (currentProfile != nullptr) {
+        Enum::CursorShapeEnum shape = static_cast<Enum::CursorShapeEnum>(currentProfile->property<int>(Profile::CursorShape));
+
+        setKeyboardCursorShape(shape);
+        setBlinkingCursorEnabled(currentProfile->blinkingCursorEnabled());
     }
 }
 
@@ -2830,12 +2831,17 @@
         _scrollWheelState.addWheelEvent(ev);
 
         _scrollBar->event(ev);
+
+        Q_ASSERT(_sessionController == nullptr);
+
         _sessionController->setSearchStartToWindowCurrentLine();
         _scrollWheelState.clearAll();
     } else if (!_readOnly) {
         _scrollWheelState.addWheelEvent(ev);
 
-        if(!_usesMouseTracking && !sessionIsPrimaryScreen() && _alternateScrolling) {
+        Q_ASSERT(_sessionController->session() == nullptr);
+
+        if(!_usesMouseTracking && _sessionController->session()->isPrimaryScreen() && _alternateScrolling) {
             // Send simulated up / down key presses to the terminal program
             // for the benefit of programs such as 'less' (which use the alternate screen)
 
@@ -2874,6 +2880,7 @@
 
 void TerminalDisplay::viewScrolledByUser()
 {
+    Q_ASSERT(_sessionController == nullptr);
     _sessionController->setSearchStartToWindowCurrentLine();
 }
 
@@ -3866,16 +3873,6 @@
     return _sessionController;
 }
 
-bool TerminalDisplay::sessionIsPrimaryScreen()
-{
-    Session *currentSession = _sessionController->session();
-    if (currentSession !=nullptr) {
-        return currentSession->isPrimaryScreen();
-    }
-
-    return true;
-}
-
 AutoScrollHandler::AutoScrollHandler(QWidget* parent)
     : QObject(parent)
     , _timerId(0)