Spencer,

Progress and Service...The Good Word

This is an excellent set of questions about the internal mechanisms that make dynamic content, like Manipulate, function correctly across environments.

The issue you're seeing—a pink panel in the Cloud—is the Wolfram System's way of indicating that a Dynamic or Manipulate expression evaluated to $Failed or encountered an error during its initial rendering in the Cloud engine.

The missing Initialization section is the source of the problem.

Could these Attributes lines explain the failure? YES

When a Manipulate expression fails in the Cloud, it's often because the functions or variables it relies on (like those from your attached Graphics.wl library) have not been loaded into the Cloud kernel before the Manipulate attempts to execute.

The presence of the Initialization section in the working notebook means that when that notebook was saved, the Wolfram System automatically captured and saved the definitions (including the temporary local symbols generated by Manipulate's internal DynamicModule) that are required for the front end to render the output without running the original code cell.

If not, could you suggest what might be causing the failure?

The failure could be caused by a missing dependency.

• When you open a Wolfram Notebook in the Cloud, it first renders the static content.
• When it reaches a dynamic object like Manipulate, it tries to resolve all the symbols.
• If a symbol (a function or variable) is needed but has not been defined (i.e., your Graphics.wl package hasn't been loaded), the expression fails, resulting in the pink panel.
• When you manually open and evaluate the cell, you force the Cloud kernel to load the dependencies, which then allows the Manipulate to run successfully.

How/why do these Attribute lines get generated?

These lines are automatically generated by the notebook front-end when it processes code containing Manipulate or DynamicModule.

• Manipulate is essentially a wrapper around DynamicModule.
• DynamicModule is the mechanism used to create dynamic, interactive elements where the local variables must persist and be synchronized between the front-end (what you see) and the back-end (the kernel).
• The system generates the Initialization data to ensure that when the notebook is rendered later (in a saved state, or on the Cloud), all internal symbols and their properties are correctly managed before any evaluation occurs.

What can I do to ensure the second version of the notebook has them?

The most common and effective solution is to ensure your package loading cell is designated as an Initialization Cell. This forces the Wolfram System to run that cell's code first whenever the notebook is opened or deployed.

A) Identify the Load Cell

Find the cell in your notebook that contains the line to load your library

Get["Graphics.wl"] or Needs["Graphics"]

B) Set as Initialization

1. Select the cell
2. Go to the Cell menu
3. Select Cell Properties
4. Check Initialization Cell

C) Re-Evaluate and Save

1. Evaluate the entire notebook once to make sure everything runs correctly
2. Save the notebook file
3. Redeploy the saved file to the Wolfram Cloud

This guarantees the Cloud kernel will execute your package loading before attempting to display the Manipulate.

What is the $CellContext context, and what does {Temporary} signify?

$CellContext

This is a special context used by the Wolfram Language to assign unique, local names to the symbols defined within a cell's evaluation scope. This prevents name clashes when using functions like Module or DynamicModule inside notebooks, ensuring that the local symbols of one Manipulate don't interfere with another.

{Temporary}

This is an Attribute applied to a symbol. It tells the Wolfram Kernel that the symbol should automatically be cleared from memory (removed) when it is no longer referenced. In the context of Manipulate/DynamicModule, it ensures that the temporary internal variables are cleaned up when the dynamic expression is closed or deleted, preventing memory leaks and clutter in the kernel.

By using the Initialization Cell property, you should be able to resolve this issue and have both versions of your notebook render correctly in the Wolfram Cloud.