Hot key doesn't work when floating?

Hi,

I'm new with RV Python, and just have been experimenting with adding and removing UI from the main window.
I want to do something like the "Session Manager" where you have a hot key, "x", to display and remove. I got that much to work except when the widget is floating.

Here's my "Hello RV" code:

from PyQt4 import QtGui, QtCore
from rv import rvtypes

class HelloRV(rvtypes.MinorMode):

    def __init__(self):
        rvtypes.MinorMode.__init__(self)
        self.init("HelloRV", None, [("key-down--X", self.toggleWidget, "X Key")])

        top_level_widgets = QtGui.QApplication.topLevelWidgets()
        self.main_window = None
        for widget in top_level_widgets:
            if isinstance(widget, QtGui.QMainWindow):
                self.main_window = widget

        self.my_dock_widget = QtGui.QDockWidget()
        label = QtGui.QLabel("This is the only thing inside the dock widget")
        self.my_dock_widget.setWidget(label)
        self.main_window.addDockWidget(QtCore.Qt.RightDockWidgetArea, self.my_dock_widget)
        self.my_dock_widget.close()

    def toggleWidget(self, event):
        if self.my_dock_widget.isHidden():
            self.my_dock_widget.show()
        else:
            self.my_dock_widget.close()

def createMode():
    return HelloRV()

It works just fine when the widget is docked, but when it's floating, it gives me this error:

ERROR: event = menu
ERROR: function = __lambda859 (void; Event ignored)
ERROR: Exception Value: exception: "invalid property name #RVTransform2D.transform.flop" 

Can somebody tell me what I'm doing wrong? Thanks!