Merge branch 'refs/heads/256-fc-persistence' into dev

# Conflicts:
#	src/gui_qt/main/mainwindow.py

src/gui_qt/main/mainwindow.py

@@ -63,6 +63,7 @@ class NMRMainWindow(QtWidgets.QMainWindow, Ui_BaseWindow):
         self.eval = None
         self.editor = None
         self._interpol_dialog = None
+        self.fc_reader = None
 
         self.logtext = QTextHandler(self)
         logger.addHandler(self.logtext)
@@ -265,14 +266,15 @@ class NMRMainWindow(QtWidgets.QMainWindow, Ui_BaseWindow):
 
     @QtCore.pyqtSlot(name='on_actionOpen_FC_triggered')
     def read_fc(self):
-        reader = QFCReader(path=self.path, parent=self)
-        reader.add_graphs(self.management.graphs.list())
-        reader.data_read.connect(self.management.add_new_data)
-        reader.exec()
+        if self.fc_reader is None:
+            self.fc_reader = QFCReader(path=self.path, parent=self)
+            self.fc_reader.data_read.connect(self.management.add_new_data)
+        else:
+            self.fc_reader(path=self.path)
+        self.fc_reader.add_graphs(self.management.graphs.list())
+        self.fc_reader.exec()
 
-        self.path = reader.path
-
-        del reader
+        self.path = self.fc_reader.path
 
     @QtCore.pyqtSlot(name='on_actionPrint_triggered')
     def print(self):