Below is the tech reason if someone is interested about it.

When try to implement this mod, I start to know why WP says it is hard to add more slots which may destroy the whole idea about why WP create his beautiful Planet View, even after WP create a beautiful scroll-able district window.

The reason why we can't use the same way as scroll-able district window to do the building window, is the official design that the building window need to always in the same containerWindow with a lot of other items together, such as building queue, trade value,.etc. So to make it scroll-able means all these items will move together...also for let the scroll-able view not so strange we need make the containerWindow have correct size as what it should, which will make some items like deposits button can't press.

If we want to resolve this we need to change whole Planet View design, and by the official restrict I think it will not beautiful as it was anymore.


Hope someone in the future may have better idea to do this and can avoid some unnecessary test steps.