You can clearly see from Skoposh's console.log:
Entering [IGSOMsg]NMH_Type::send(5258)
Entering NMH_Type::send(5258)
Entering [CanvasCursor]GuiCanvas::popDialog(Canvas, newMessageHud)
Entering newMessageHud::onSleep(5255)
base/client/scripts/allClientScripts.cs (17167): Unable to find object: 'NoShiftMoveMap' attempting to call function 'pop'
Leaving newMessageHud::onSleep() - return
Entering [CanvasCursor]GuiCanvas::checkCursor(Canvas)
Entering [CanvasCursor]GuiCanvas::checkTabFocus(Canvas)
Leaving [CanvasCursor]GuiCanvas::checkTabFocus() - return
Leaving [CanvasCursor]GuiCanvas::checkCursor() - return
Leaving [CanvasCursor]GuiCanvas::popDialog() - return
Leaving NMH_Type::send() - return
Leaving [IGSOMsg]NMH_Type::send() - return
Its entering a package made by IGSO which is clearly screwing it up, since nobody who doesn't have IGSO can duplicate this error. So yeah, IGSO is a piece of stuff.