Index: src/sas/qtgui/Plotting/BoxSum.py
===================================================================
--- src/sas/qtgui/Plotting/BoxSum.py	(revision 0849aec6ceb97781213ef369f98e5eb61ec8cad3)
+++ src/sas/qtgui/Plotting/BoxSum.py	(revision 6280464f8c6799ad2cb851c2fbb6ad66dc0fe2ba)
@@ -11,5 +11,4 @@
 
 class BoxSum(QtWidgets.QDialog, Ui_BoxSumUI):
-    apply_signal = QtCore.pyqtSignal(tuple, str)
     def __init__(self, parent=None, model=None):
         super(BoxSum, self).__init__()
@@ -24,5 +23,5 @@
 
         self.model = model
-        self.mapper = QtGui.QDataWidgetMapper()
+        self.mapper = QtWidgets.QDataWidgetMapper()
         self.mapper.setModel(self.model)
 
@@ -32,9 +31,9 @@
         self.mapper.addMapping(self.txtCenterX, 2)
         self.mapper.addMapping(self.txtCenterY, 3)
-        self.mapper.addMapping(self.lblAvg, 4, "text")
-        self.mapper.addMapping(self.lblAvgErr, 5, "text")
-        self.mapper.addMapping(self.lblSum, 6, "text")
-        self.mapper.addMapping(self.lblSumErr, 7, "text")
-        self.mapper.addMapping(self.lblNumPoints, 8, "text")
+        self.mapper.addMapping(self.lblAvg, 4, b"text")
+        self.mapper.addMapping(self.lblAvgErr, 5, b"text")
+        self.mapper.addMapping(self.lblSum, 6, b"text")
+        self.mapper.addMapping(self.lblSumErr, 7, b"text")
+        self.mapper.addMapping(self.lblNumPoints, 8, b"text")
 
         # Populate the widgets with data from the first column
@@ -43,2 +42,11 @@
         self.setFixedSize(self.minimumSizeHint())
 
+        # Handle the Apply button click
+        self.buttonBox.button(QtWidgets.QDialogButtonBox.Close).clicked.connect(self.onClose)
+
+    def onClose(self):
+        """
+        close the window containing this panel
+        """
+        self.close()
+
Index: src/sas/qtgui/Plotting/Plotter.py
===================================================================
--- src/sas/qtgui/Plotting/Plotter.py	(revision 304d082fdf2d11b8729c78132d385223c5c29054)
+++ src/sas/qtgui/Plotting/Plotter.py	(revision 6280464f8c6799ad2cb851c2fbb6ad66dc0fe2ba)
@@ -160,5 +160,5 @@
 
         # refresh canvas
-        self.canvas.draw()
+        self.canvas.draw_idle()
 
     def createContextMenu(self):
Index: src/sas/qtgui/Plotting/Plotter2D.py
===================================================================
--- src/sas/qtgui/Plotting/Plotter2D.py	(revision 304d082fdf2d11b8729c78132d385223c5c29054)
+++ src/sas/qtgui/Plotting/Plotter2D.py	(revision 6280464f8c6799ad2cb851c2fbb6ad66dc0fe2ba)
@@ -123,5 +123,5 @@
         """
         # Toggle the scale
-        zmin_temp = self.zmin
+        zmin_temp = self.zmin if self.zmin else MIN_Z
         zmax_temp = self.zmax
         # self.scale predefined in the baseclass
Index: src/sas/qtgui/Plotting/PlotterBase.py
===================================================================
--- src/sas/qtgui/Plotting/PlotterBase.py	(revision 304d082fdf2d11b8729c78132d385223c5c29054)
+++ src/sas/qtgui/Plotting/PlotterBase.py	(revision 6280464f8c6799ad2cb851c2fbb6ad66dc0fe2ba)
@@ -34,4 +34,7 @@
         self.manager = manager
         self.quickplot = quickplot
+
+        #plt.style.use('ggplot')
+        plt.style.use('seaborn-darkgrid')
 
         # a figure instance to plot on
Index: src/sas/qtgui/Plotting/Slicers/BoxSum.py
===================================================================
--- src/sas/qtgui/Plotting/Slicers/BoxSum.py	(revision 0849aec6ceb97781213ef369f98e5eb61ec8cad3)
+++ src/sas/qtgui/Plotting/Slicers/BoxSum.py	(revision 6280464f8c6799ad2cb851c2fbb6ad66dc0fe2ba)
@@ -6,5 +6,5 @@
 from PyQt5 import QtGui
 
-from sas.qtgui.Utilities.GuiUtils import formatNumber
+from sas.qtgui.Utilities.GuiUtils import formatNumber, toDouble
 
 from .BaseInteractor import BaseInteractor
@@ -137,8 +137,8 @@
         """
         params = {}
-        params["Height"] = float(self.model().item(0, 0).text())
-        params["Width"] = float(self.model().item(0, 1).text())
-        params["center_x"] = float(self.model().item(0, 2).text())
-        params["center_y"] = float(self.model().item(0, 3).text())
+        params["Height"] = toDouble(self.model().item(0, 0).text())
+        params["Width"] = toDouble(self.model().item(0, 1).text())
+        params["center_x"] = toDouble(self.model().item(0, 2).text())
+        params["center_y"] = toDouble(self.model().item(0, 3).text())
         self.update_model = False
         self.setParams(params)
