Drop the "Lua" in Lua Action Buttons:

Removed the term "Lua", because users were turned off by something they didn't understand.
A special-case Lua script ("Shortcut") allows the user to select an arbitrary Action.
The "Shortcut" script is selected by default, and in this case there is no "Type" or "Author" displayed.
Action-Buttons may still trigger Lua scripts, as a secondary function.

scripts/access_action.lua

@@ -0,0 +1,37 @@
+ardour {
+	["type"]    = "EditorAction",
+	name        = "Shortcut",
+	license     = "MIT",
+	author      = "me",
+	description = [[Trigger a keyboard shortcut.  You will be prompted for the shortcut's action in the next step.]]
+}
+
+function action_params ()
+	local actionlist = {
+		{
+			type = "dropdown", key = "action", title = "Action", values = ArdourUI:actionlist(),
+			default = "Save"
+		}
+	}
+
+	local rv = LuaDialog.Dialog ("Select Action", actionlist):run ()
+	if not rv then -- user cancelled
+		return { ["x-script-abort"] = { title = "", preseeded = true} }
+	end
+
+	local action = rv["action"]
+	local name = "Shortcut - " .. action
+	return {
+		["action"] = { title = "Action to trigger", default = action, preseeded = true},
+		["x-script-name"] = { title = "Unique Script name", default = name, preseeded = true},
+	}
+end
+
+function factory (params) return function ()
+	local p = params or { }
+	local as = assert (p["action"])
+	local sp = assert (as:find('/'))
+	local group = assert (as:sub(0, sp - 1))
+	local item = assert (as:sub(1 + sp))
+	Editor:access_action (group, item)
+end end