diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 8e4775bc..8a592c55 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -102,9 +102,11 @@ set(DOCKS_INSTALLABLE_INCLUDES
 set(DOCKS_INSTALLABLE_PRIVATE_INCLUDES
     private/DragController_p.h
     private/Draggable_p.h
+    private/DropArea_p.h
     private/DropIndicatorOverlayInterface_p.h
     private/FloatingWindow_p.h
     private/Frame_p.h
+    private/MultiSplitter_p.h
     private/SideBar_p.h
     private/TitleBar_p.h
     private/WindowBeingDragged_p.h
diff --git a/src/MainWindowBase.cpp b/src/MainWindowBase.cpp
index f81b53cd..c5438026 100644
--- a/src/MainWindowBase.cpp
+++ b/src/MainWindowBase.cpp
@@ -28,6 +28,7 @@
 #include "WidgetResizeHandler_p.h"
 #include "FrameworkWidgetFactory.h"
 #include "DropAreaWithCentralFrame_p.h"
+#include "LayoutSaver_p.h"
 
 using namespace KDDockWidgets;
 
diff --git a/src/fwd_headers/kddockwidgets/private/DragController_p.h b/src/fwd_headers/kddockwidgets/private/DragController_p.h
new file mode 100644
index 00000000..de8165a4
--- /dev/null
+++ b/src/fwd_headers/kddockwidgets/private/DragController_p.h
@@ -0,0 +1,12 @@
+/*
+  This file is part of KDDockWidgets.
+
+  SPDX-FileCopyrightText: 2020-2021 Klarälvdalens Datakonsult AB, a KDAB Group company <info@kdab.com>
+  Author: Sergio Martins <sergio.martins@kdab.com>
+
+  SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only
+
+  Contact KDAB at <info@kdab.com> for commercial licensing options.
+*/
+
+#include "../../../private/DragController_p.h"