How is the ArcMap Table of Contents mode stored?

Question

The ArcMap table of Contents has several display modes - List By Drawing Order; List By Source etc (described here).

How or where this is saved? Is it saved within the MXD file or is there a system setting somewhere that controls it?

Answer 1

What you are asking about is called the "Last Tab Index", and it is a user-based setting stored in the registry and not in any MXDs. For ArcGIS 10.8.x, the registry setting is:

[HKEY_CURRENT_USER\SOFTWARE\ESRI\Desktop10.8\ArcMap\TOC\Views]
"Last Tab Index"=dword:00000000

The corresponding index values are:

0 = List By Drawing Order
1 = List By Source
2 = List By Visibility
3 = List By Selection

Any value besides one of those four will be changed at start-up back to 0 - List By Drawing Order.

Answer 2

They are just buttons that alter the view of the TOC. The status will be recorded within the MXD. You would need to use ArcObjects to interact with it in a programmatic way.

Here is the VBA you could run within the mxd that would return the actively selected button:

Public Sub Test()
    Dim pMXD As IMxDocument
    Set pMXD = ThisDocument
    Dim pCV As IContentsView3
    Set pCV = pMXD.CurrentContentsView
    Debug.Print pCV.Name
End Sub