diff --git a/src/commonfrontend/matrix/MatrixView.cpp b/src/commonfrontend/matrix/MatrixView.cpp
--- a/src/commonfrontend/matrix/MatrixView.cpp
+++ b/src/commonfrontend/matrix/MatrixView.cpp
@@ -56,6 +56,7 @@
 #include <QThreadPool>
 #include <QMutex>
 #include <QProcess>
+#include <QHeaderView>
 
 #include <KLocale>
 #include <QIcon>
diff --git a/src/kdefrontend/dockwidgets/CantorWorksheetDock.cpp b/src/kdefrontend/dockwidgets/CantorWorksheetDock.cpp
--- a/src/kdefrontend/dockwidgets/CantorWorksheetDock.cpp
+++ b/src/kdefrontend/dockwidgets/CantorWorksheetDock.cpp
@@ -30,6 +30,7 @@
 #include "CantorWorksheetDock.h"
 #include "backend/cantorWorksheet/CantorWorksheet.h"
 #include <KParts/ReadWritePart>
+#include <QAction>
 
 CantorWorksheetDock::CantorWorksheetDock(QWidget* parent): QWidget(parent), m_worksheet(nullptr), m_initializing(false) {
 	ui.setupUi(this);
diff --git a/src/kdefrontend/spreadsheet/FunctionValuesDialog.h b/src/kdefrontend/spreadsheet/FunctionValuesDialog.h
--- a/src/kdefrontend/spreadsheet/FunctionValuesDialog.h
+++ b/src/kdefrontend/spreadsheet/FunctionValuesDialog.h
@@ -38,6 +38,7 @@
 class TreeViewComboBox;
 class AspectTreeModel;
 class QPushButton;
+class QLineEdit;
 class FunctionValuesDialog : public QDialog {
 	Q_OBJECT
 
diff --git a/src/kdefrontend/widgets/FITSHeaderEditNewKeywordDialog.h b/src/kdefrontend/widgets/FITSHeaderEditNewKeywordDialog.h
--- a/src/kdefrontend/widgets/FITSHeaderEditNewKeywordDialog.h
+++ b/src/kdefrontend/widgets/FITSHeaderEditNewKeywordDialog.h
@@ -33,6 +33,7 @@
 #include <QDialog>
 
 class QPushButton;
+class QAbstractButton;
 class FITSHeaderEditNewKeywordDialog : public QDialog {
 	Q_OBJECT