Sort order not updated when custom column config changed

[Lefteous]

Win7, x64, TC9, beta4

1. Define a view mode that has uses an existing custom config as primary sort order. The sort order should be the last column.
2. Back in custom column view config delete the last column of that columns definition.
3. Open view mode config. The last column is still displayed as sort order although it doesn't exist anymore.
4. Close and reopen the dialog. Now the sort order dropdown has no selected item.

Expected: Updates to the custom column view must be detected in all view modes where it is used. There should be a proper handling of the sort order in view mode when available columns change. The simplest solution in this case would be set the sort order to 'Unchanged'.
It would be great if the sort order in the view modes could be preserved when there is a change (delete column before sort column or change column order) in the associated custom column view.

[ghisler(Author)]

Currently this isn't planned. It would create a mess when the user just removes a column to add another one (many people click apply after each step).

[Lefteous]

It would create a mess

It's already there.

Maybe you can check if the index used for the sort column still has the same content. Otherwise set the sort column to 'Unchanged'?