diff --git a/qucs/components/libcomp.cpp b/qucs/components/libcomp.cpp
index 3e4150f9..e03eafdf 100644
--- a/qucs/components/libcomp.cpp
+++ b/qucs/components/libcomp.cpp
@@ -18,13 +18,11 @@
 #include <QtGui>
 #include "libcomp.h"
 #include "qucs.h"
-//Added by qt3to4:
-#include <QTextStream>
 #include "main.h"
 #include "schematic.h"
 
+#include <QTextStream>
 #include <QDir>
-#include <QFileInfo>
 #include <QRegExp>
 
 #include <math.h>
diff --git a/qucs/components/libcomp.h b/qucs/components/libcomp.h
index 59c5178b..f2a5da28 100644
--- a/qucs/components/libcomp.h
+++ b/qucs/components/libcomp.h
@@ -19,8 +19,9 @@
 #define LIBCOMP_H
 
 #include "component.h"
-//Added by qt3to4:
-#include <QTextStream>
+
+class QTextStream;
+class QString;
 
 
 class LibComp : public MultiViewComponent  {
diff --git a/qucs/components/optimizedialog.h b/qucs/components/optimizedialog.h
index 658b77e3..04c787f0 100644
--- a/qucs/components/optimizedialog.h
+++ b/qucs/components/optimizedialog.h
@@ -20,8 +20,6 @@
 
 #include <QDialog>
 #include <QRegExp>
-//Added by qt3to4:
-#include <Q3VBoxLayout>
 
 class Schematic;
 class Optimize_Sim;
diff --git a/qucs/components/spicefile.h b/qucs/components/spicefile.h
index 9593fc97..d94e1147 100644
--- a/qucs/components/spicefile.h
+++ b/qucs/components/spicefile.h
@@ -17,13 +17,10 @@
 
 #ifndef SPICEFILE_H
 #define SPICEFILE_H
-#include <QtGui>
 #include "component.h"
 
 #include <QObject>
 #include <QDateTime>
-//Added by qt3to4:
-#include <QTextStream>
 
 class QProcess;
 class QTextStream;
diff --git a/qucs/components/subcircuit.cpp b/qucs/components/subcircuit.cpp
index 8c12b13e..a842bdbb 100644
--- a/qucs/components/subcircuit.cpp
+++ b/qucs/components/subcircuit.cpp
@@ -18,14 +18,11 @@
 #include <QtGui>
 #include "subcircuit.h"
 #include "qucs.h"
-//Added by qt3to4:
-#include <QTextStream>
 #include "schematic.h"
 #include "main.h"
 
-#include <QDir>
+#include <QTextStream>
 #include <QFileInfo>
-#include <QRegExp>
 
 #include <math.h>
 #include <limits.h>
diff --git a/qucs/components/verilogfile.cpp b/qucs/components/verilogfile.cpp
index 00e0b2a3..cad135dd 100644
--- a/qucs/components/verilogfile.cpp
+++ b/qucs/components/verilogfile.cpp
@@ -17,13 +17,11 @@
 #include <QtGui>
 #include "verilogfile.h"
 #include "qucs.h"
-//Added by qt3to4:
-#include <QTextStream>
 #include "main.h"
 #include "schematic.h"
 
+#include <QTextStream>
 #include <QRegExp>
-#include <QDir>
 #include <QFileInfo>
 
 
diff --git a/qucs/components/verilogfile.h b/qucs/components/verilogfile.h
index c7bc2ab1..a6e4a647 100644
--- a/qucs/components/verilogfile.h
+++ b/qucs/components/verilogfile.h
@@ -19,8 +19,9 @@
 #define VERILOGFILE_H
 
 #include "component.h"
-//Added by qt3to4:
-#include <QTextStream>
+
+class QTextStream;
+class QString;
 
 
 class Verilog_File : public MultiViewComponent  {
diff --git a/qucs/components/vhdlfile.cpp b/qucs/components/vhdlfile.cpp
index d627bed7..58abad5e 100644
--- a/qucs/components/vhdlfile.cpp
+++ b/qucs/components/vhdlfile.cpp
@@ -17,13 +17,11 @@
 #include <QtGui>
 #include "vhdlfile.h"
 #include "qucs.h"
-//Added by qt3to4:
-#include <QTextStream>
 #include "main.h"
 #include "schematic.h"
 
+#include <QTextStream>
 #include <QRegExp>
-#include <QDir>
 #include <QFileInfo>
 
 
diff --git a/qucs/components/vhdlfile.h b/qucs/components/vhdlfile.h
index 1a344359..3fccd122 100644
--- a/qucs/components/vhdlfile.h
+++ b/qucs/components/vhdlfile.h
@@ -19,8 +19,9 @@
 #define VHDLFILE_H
 
 #include "component.h"
-//Added by qt3to4:
-#include <QTextStream>
+
+class QTextStream;
+class QString;
 
 
 class VHDL_File : public MultiViewComponent  {