What do you mean "doesn't appear in-game today"?
- It isn't showing when I load into the world?
- It isn't show after I click a button that makes it visible?
- It isn't showing after I issue the command Show_Window Custom.CoinWeight?
In order for EQ2 to make a window visible it has to be make visible via the command Show_Window and this includes each time you run EQ2. After that you can set the visible property of that window to true or false to work.