Added BusyCursor for notify manager is working

https://github.com/QubesOS/qubes-issues/issues/4744

qubesmanager/settings.py

@@ -138,6 +138,8 @@ class VMSettingsWindow(ui_settingsdlg.Ui_SettingsDialog, QtGui.QDialog):
     def __init__(self, vm, qapp, init_page="basic", parent=None):
         super(VMSettingsWindow, self).__init__(parent)
 
+        QtGui.QApplication.setOverrideCursor(QtCore.Qt.BusyCursor)
+
         self.vm = vm
         self.qapp = qapp
         self.threads_list = []
@@ -224,6 +226,8 @@ class VMSettingsWindow(ui_settingsdlg.Ui_SettingsDialog, QtGui.QDialog):
             self.refresh_apps_button.clicked.connect(
                 self.refresh_apps_button_pressed)
 
+        QtGui.QApplication.restoreOverrideCursor()
+
     def clear_threads(self):
         for thread in self.threads_list:
             if thread.isFinished():
@@ -276,6 +280,8 @@ class VMSettingsWindow(ui_settingsdlg.Ui_SettingsDialog, QtGui.QDialog):
     def __save_changes__(self):
         ret = []
 
+        QtGui.QApplication.setOverrideCursor(QtCore.Qt.BusyCursor)
+
         try:
             ret_tmp = self.__apply_basic_tab__()
             if ret_tmp:
@@ -313,6 +319,8 @@ class VMSettingsWindow(ui_settingsdlg.Ui_SettingsDialog, QtGui.QDialog):
         except Exception as ex:  # pylint: disable=broad-except
             ret += [self.tr("Applications tab:"), repr(ex)]
 
+        QtGui.QApplication.restoreOverrideCursor()
+
         utils.debug('\n'.join(ret))
         return ret