I'm facing issues in showing UTF-8 strings in Edit widgets.
Below a simple example, the dotted rect character is shown as space on my PC with LuaRT 1.3.1
local ui = require 'ui'
win = ui.Window('Demo', 'single', 400, 300)
e = ui.Edit(win, '', 10, 10, 300, 200)
e.readonly = true
e.font = 'Consolas'
e.richtext = false
e.text = 'A'..string.rep('░', 10)..'B'
win:show()
while win.visible do ui.update() end
