Fix program not fitting on low resolution screens

Lowest vertical screen size that I could test and made sure fit is 768 pixels on a field laptop.

Closes #180 (closed)

sohstationviewer/view/plotting/gps_plot/gps_dialog.py

@@ -31,7 +31,7 @@ class GPSWidget(QtWidgets.QWidget):
         # one point for each coordinate.
         self.unique_gps_points: Optional[List[GPSPoint]] = None
 
-        self.fig = Figure(figsize=(6, 6), dpi=100)
+        self.fig = Figure(figsize=(6, 6), dpi=100, facecolor='#ECECEC')
         self.canvas = Canvas(self.fig)
         self.canvas.mpl_connect('pick_event', self.on_pick_event)