All GUIs need a cleanup. The filterlist and insert direction interface need to be a separate GUIComponent(like GUIButton/GUITextfield).

I'm going to be working on this stuff today.

Thanks! Filtering Chests are harder than I thought they would be, so progress is slow :(

I might be going a little overboard with this, but I'm kind of totally redoing the entire GUI.

That screen (GuiAdvancedFilteredBlockExtender) only implements the methods initGui (to add all the sub elements) and drawGuiContainerBackgroundLayer (to draw it's own background and nothing else). Each button, text, filter option, etc, is its own Gui element that can be added as a child to any other of the Gui elements that I've implemented.

Not sure when this stuff will be commit-ready, though.

That looks way better than it was! Much more organized and a lot more clear. Thank you for doing this!

More pictures:

That should be all the GUIs (except filtering chest). There are a lot of interconnected changes that I made while doing this GUI stuff though, so I'm going to try to sort things out and only commit the relevant chunks of code if I can.