diff --git a/DCPlugin.pro b/DCPlugin.pro
index b968520..817abf8 100644
--- a/DCPlugin.pro
+++ b/DCPlugin.pro
@@ -4,7 +4,7 @@ CONFIG += plugin
 #CONFIG -= app_bundle
 #QT += widgets
 QT -= gui
-QT += widgets serialport
+QT += serialport
 
 INCLUDEPATH += $${PWD}/plugins
 INCLUDEPATH += $${PWD}/include
diff --git a/include/com.h b/include/com.h
index 69a8ea4..44b0021 100644
--- a/include/com.h
+++ b/include/com.h
@@ -3,7 +3,7 @@
 #ifndef SER_H
 #define SER_H
 #include <stdint.h>
-#include <QMainWindow>
+#include <QObject>
 #include <QString>
 #include <QTimer>
 #include <QSerialPort>
@@ -15,7 +15,7 @@
 // display all inputs and outputs in output window:
 //#define PRINTALLDEBUGS          1
 
-class T_com : public QMainWindow        //,  public QPlainTextEdit
+class T_com : public QObject        //,  public QPlainTextEdit
 {
     Q_OBJECT
 
@@ -45,7 +45,7 @@ private slots:
 
 
 public:
-    T_com(QWidget *parent = nullptr);
+    T_com(QObject *parent = nullptr);
     ~T_com();
 
     QTimer *serRecTime;
diff --git a/include/datIf.h b/include/datIf.h
index 465691f..f1f2c07 100644
--- a/include/datIf.h
+++ b/include/datIf.h
@@ -12,7 +12,7 @@
 #include "dcBL.h"
 
 
-#include <QMainWindow>
+#include <QObject>
 #include <QString>
 #include <QTimer>
 #include <QDebug>
@@ -278,7 +278,7 @@
 
 
 
-class T_datif : public QMainWindow
+class T_datif : public QObject
 {
     Q_OBJECT    
 
@@ -315,7 +315,7 @@ private slots:
     void StoredRecData();
 
 public:
-    T_datif(QWidget *parent = nullptr);
+    T_datif(QObject *parent = nullptr);
 
     T_prot *getProt() { return myDCIF; }
     T_prot const *getProt() const { return myDCIF; }
diff --git a/include/prot.h b/include/prot.h
index 93304c0..33a9845 100644
--- a/include/prot.h
+++ b/include/prot.h
@@ -3,7 +3,7 @@
 #define SERIAL_FRAME_H
 
 #include <stdint.h>
-#include <QMainWindow>
+#include <QObject>
 #include <QString>
 #include <QTimer>
 #include "tslib.h"
@@ -43,7 +43,7 @@
 #define     STARTSIGN_RECEIVE_LONG          0x5D
 
 
-class T_prot : public QMainWindow
+class T_prot : public QObject
 {
     Q_OBJECT
 
diff --git a/src/com.cpp b/src/com.cpp
index 8c28383..6ba7d3e 100644
--- a/src/com.cpp
+++ b/src/com.cpp
@@ -49,7 +49,7 @@ bool T_com::readFromSerial(QByteArray &data, uint16_t &sendLength)
 // -------------------------------------------------------------------------------------------------------------
 
 
-T_com::T_com(QWidget *parent) : QMainWindow(parent)
+T_com::T_com(QObject *parent) : QObject(parent)
 {
     // port settings come from tabCom->Sdata->serial
 
diff --git a/src/datIf.cpp b/src/datIf.cpp
index 9075f82..a1490c8 100644
--- a/src/datIf.cpp
+++ b/src/datIf.cpp
@@ -19,7 +19,7 @@ static uint8_t cycl_running;
 
 //static bool     datif_DCdataValid;
 
-T_datif::T_datif(QWidget *parent) : QMainWindow(parent)
+T_datif::T_datif(QObject *parent) : QObject(parent)
 {
 
     myDCIF = new T_prot();