Druid with Monarch -- input not switched

[New to Druid and to Monarch, fairly new to Defold]

I have a simple project, 2 Monarch screens (collections managed by Monarch), buttons on each. Pressing a button in each switches to the other screen. The buttons on one screen work, the button on the second screen does not. The buttons and the scripts are copies of each other – and I have re-created them several times to be certain.

The button in the second screen does not do mouse-over or get any input. It does not matter which screen I start up with, screen 2 does not work even if it is the first screen shown.

I don’t know what to look for, they seem identical. What am I missing to make buttons on the second screen work? What else is needed to activate the buttons? (set_enabled makes no difference) Is there some simple flag I have to set to enable druid actions on the second screen? Here is the code:

local druid = require(“druid.druid”)
local monarch = require “monarch.monarch”

local function got_topic(self)
– go back to the title screen
monarch.show(“title”)
print(“got_title”)
end

function init(self)
self.druid = druid.new(self)
self.how_to = self.druid:new_button(“topic_button/root”, got_topic)
end

– “final” is a required function for the correct Druid workflow
function final(self)
self.druid:final()
end

– “update” is used in progress bar, scroll, and timer basic components
function update(self, dt)
self.druid:update(dt)
end

– “on_message” is used for specific Druid events, like language change or layout change
function on_message(self, message_id, message, sender)
self.druid:on_message(message_id, message, sender)
end

– “on_input” is used in almost all Druid components
– The return value from druid:on_input is required!
function on_input(self, action_id, action)
return self.druid:on_input(action_id, action)
end

I seem to have solved it, though I am not positive I know what was wrong. I fixed it by comparing in a text editor the two xxx_gui.gui files. The one that worked had a script:… line at the top, and the one that did not work did not have the script: … line at the top. I added that script line (fixed for the correct script), and it all worked. Presumably I missed a step in linking the gui and the script.