fixed problem with setting color from context menu

src/gui_qt/main/mainwindow.py

@@ -1078,3 +1078,7 @@ class NMRMainWindow(QtWidgets.QMainWindow, Ui_BaseWindow):
     def show_version(self):
         from nmreval.version import __version__
         QtWidgets.QMessageBox.about(self, 'Version', f'Build date of AppImage: {__version__}')
+
+    @QtCore.pyqtSlot(name='on_actionTNMH_model_triggered')
+    def calculate_tnmh(self):
+        print('tnmh')