Action section "hidden" cells?

[wapperdude]

With regards to Actions Prompt cell, VBA won't barf over it, but, it does nothing. 

@Surrogate:  tried your code in V2019 and saw now visible results.  Certainly no visible behavior.  Only the bones remain.

@Vojo:  Sorry.  The discovery, itself, is what's "new".  What was discovered was quite old.  Archeology at its best.

Prompt Cell (Actions Section)
 
Beginning with Visio 2002, this cell is no longer used.

Remarks
In earlier versions of Visio, this cell specified a descriptive prompt that appeared in the status bar when you selected the corresponding shortcut command.

[Paul Herber]

A cell like this could be used for hiding data within the shape. The cell could still be written to using a numerical index, but the data would not be visible in the shapoesheet.
Who needs cryptography or steganography when you can hide data within a Visio shape!
Now, where is Pat Pending?

[Surrogate]

6 years ago we have thread about hidden ShapeSheet's cells in Russian Visio Forum (read it via Bing Translate service).
You can find a lot hidden/unused cells in ShapeSheet 

[Gustavo]

To hide data is a good use! a password or hash would be hidden even for a user with decent programming knowledge. But is it possible to retrieve data from these cells?

[vojo]

so exactly how would hidden cells work if they are ultimately in xml when drawing saved?

And if you did have hidden cells....great way to ship a virus around
- virus sits in a hidden cell(s)….10 bytes to phone home or say 1MB of actual virus
- launcher virus looking for the shape on your system (downloaded from some public site because it looked cool) and launches the virus.

[Surrogate]

so exactly how would hidden cells work if they are ultimately in xml when drawing saved?

If document where used these hidden cells save as vdx file format, secret formulas stop work !

[vojo]

maybe I am wrong, but I thought around 2013, drawing (even VBA) were saved in an xml format.

[Gustavo]

It would be nice to have these "hidden" or discontinued cells/columns listed for future references, in order to avoid confutions or headscratches. The VSDX File Format specs https://interoperability.blob.core.windows.net/files/MS-VSDX/%5bMS-VSDX%5d-180724.pdf  has some information about "hidden" cells with actual use, but there's barely information for discontinued cells that remain in the shapesheet anywhere.

[wapperdude]

Since these are hidden, thus, unknown, the risk of using one seems extremely small.  Except for this thread, I'd say most users are unaware of their existence.  Indeed, it takes code to discover them.  It's probably bad form to keep them.  It may keep old code from crashing, but it does possibly allow for incorrect execution of said code.  I think getting error msg is preferable.