What does the code look like that is giving the error?
try accessing it using FlexGlobals.topLevelApplication instead, and see if it yields same error.
You might have to type cast it. You could also use Application.application
But either of those are not the right approaches...
You should create a property in the custom component and before popping up the TitleWindow you should pass the book to this property.
Your advice is appreciated.
I know that my method is not strict OOP. I'm a beginner. I'm just trying to get something to work.
I have a class file for the popup TitleWindow, but as far as I can tell I can only assign values to controls within the form. I have a variable (which I assume is what you mean by property) setup in the class file, but I don't know how to transfer the value from the main app to it. For example: from the main app I can assign popup.textbox.text = "some book" from the main app. How do I assign a value to a variable? I discovered I can't assign popup.someVariable = "some book".
I also tried Application.application but I couldn't get that to work. Is Application.application just placeholder text to which I would apply my own component names? I get undefined errors and can't determine which classes I need to import in order for this to work (I guess).
Could you give me a hint?