title: Have a popupmenu appear on a popupmenu on right-click
body: <p>I have a wx Popupmenu appear when I left-click on a toolbar <code>LabelTool</code>. I already have a binding to have a handler run when I left click an item in the menu, but I want another popup menu to appear when I right click an item in the original popup menu. I've already tried binding it to <code>wx.EVT_RIGHT_DOWN</code> but it doesn't do it. Whenever I try right clicking on a menu object, it seems it still calls the <code>wx.EVT_MENU</code>, which calls the same handler as a left-click would. How would I implement this?</p>