ChiliUi is a framework still in development by author JK. It's a very flexible class based framework, with it's structure derived from Delphi. It has most of the basic components you expect a framework like for example Swing in java must have. It might feel a bit daunting at first to get started but with a little reverse engineering and this tutorial page you'll get a long way !
Download it , and put the extracted files in LuaUi/widgets. It should run out of the box, but user experiences have been conflicted on that. If you are in trouble getting Chili to run, I advice to login to the lobby and join /j moddev. People there will help you figure it out. I could write something here, but by the time it's written , someone else probably has another problem installing it !
Chili Component Hiearchy
object |_font |_screen |_control |_button |_image |_checkbox |_colorbars |_label |_layoutpanel |_imagelistview |_grid |_stackpanel |_treeview |_panel |_progressbar |_scrollpanel |_textbox |_trackbar |_treeview |_treeviewnode |_window