diff --git a/sohstationviewer/view/plotting/plotting_widget/multi_threaded_plotting_widget.py b/sohstationviewer/view/plotting/plotting_widget/multi_threaded_plotting_widget.py
index f8cec92810a379ae2c31ed608f884c90b56af1be..919261c3da3236f88fe084ab0109c1711ac35add 100644
--- a/sohstationviewer/view/plotting/plotting_widget/multi_threaded_plotting_widget.py
+++ b/sohstationviewer/view/plotting/plotting_widget/multi_threaded_plotting_widget.py
@@ -74,7 +74,7 @@ class MultiThreadedPlottingWidget(PlottingWidget):
         :param time_ticks_total: max number of tick to show on time bar
         :param is_waveform: True if this is a WaveformWidget, otherwise False
         """
-
+        self.zoom_marker1_shown = False
         self.key = key
         self.processing_log = []  # [(message, type)]
         self.gap_bar = None
diff --git a/sohstationviewer/view/plotting/time_power_squared_dialog.py b/sohstationviewer/view/plotting/time_power_squared_dialog.py
index 5e533b53b591894908a59bca12eb8899c5dde0d3..ae3847d83641979114d6f88d86afe4e0b9d2cdbb 100755
--- a/sohstationviewer/view/plotting/time_power_squared_dialog.py
+++ b/sohstationviewer/view/plotting/time_power_squared_dialog.py
@@ -86,6 +86,7 @@ class TimePowerSquaredWidget(plotting_widget.PlottingWidget):
         :param start_tm: requested start time to read
         :param end_tm: requested end time to read
         """
+        self.zoom_marker1_shown = False
         self.is_working = True
         self.set_key = key
         self.plotting_data1 = d_obj.waveform_data[key]