correct pref_order is the order of plotting_data1

sohstationviewer/view/plotting/plotting_widget/multi_threaded_plotting_widget.py

 # Define functions to call processor
 
-from typing import Tuple, Union, Dict, List
+from typing import Tuple, Union, Dict, List, Optional
 
 from PySide6 import QtCore
 
@@ -33,8 +33,15 @@ class MultiThreadedPlottingWidget(PlottingWidget):
     def __init__(self, *args, **kwargs):
         PlottingWidget.__init__(self, *args, **kwargs)
         self.data_processors: List[PlottingChannelProcessor] = []
-        # pref_order: order of channels to be plotted
+        # order of channels to be plotted
         self.pref_order: List[str] = []
+        # object of data to be plotted
+        self.data_object: Optional[GeneralData] = None
+        # id of data set to be plotted
+        self.data_set_id: Union[str, Tuple[str, str]] = ''
+        self.start_tm: float = 0
+        self.end_tm: float = 0
+
         # Only one data processor can run at a time, so it is not a big problem
         #
         self.thread_pool = QtCore.QThreadPool()
@@ -127,7 +134,6 @@ class MultiThreadedPlottingWidget(PlottingWidget):
             chan_order, list(plotting_data.keys()))
         chan_order = remove_not_found_chans(
             chan_order, list(plotting_data.keys()), self.processing_log)
-        self.pref_order = chan_order
 
         not_plot_chans = []
         for chan_id in chan_order:
@@ -231,7 +237,7 @@ class MultiThreadedPlottingWidget(PlottingWidget):
                 return
             chan_order1 = self.get_plotting_info(self.plotting_data1, True)
             chan_order2 = self.get_plotting_info(self.plotting_data2)
-
+            self.pref_order = chan_order1
             self.plotting_preset()
 
             self.create_plotting_channel_processors(