API: Move action propagation of shortcuts on Stacked Widget (Plots, VarExp) to _update_option

[goanpeca]

Se plots/main_widget.py

    def update_actions(self):
        value = False
        widget = self.current_widget()
        figviewer = None
        if widget:
            figviewer = widget.figviewer
            thumbnails_sb = widget.thumbnails_sb
            value = figviewer.figcanvas.fig is not None

        for __, action in self.get_actions().items():
            if action and action not in [self.mute_action,
                                         self.outline_action,
                                         self.fit_action]:
                action.setEnabled(value)

                # IMPORTANT: Since we are defining the main actions in here
                # and the context is WidgetWithChildrenShortcut we need to
                # assign the same actions to the children widgets in order
                # for shortcuts to work
                if figviewer:
                    figviewer_actions = figviewer.actions()
                    thumbnails_sb_actions = thumbnails_sb.actions()

                    if action not in figviewer_actions:
                        figviewer.addAction(action)

                    if action not in thumbnails_sb_actions:
                        thumbnails_sb.addAction(action)

        self.zoom_disp.setEnabled(value)