Hello,

I am trying to achieve the following:

A 'related list' view of a custom object (Foo), which can be added to an existing standard object (Case).  The custom object Foo has a Master/Slave relation with Case.  Each 'Foo' item in the list needs to display either its status, or two action buttons/links.  The choice is conditional on a status field from Foo.

The button/link action may update other related lists.  The standard object (Case) page therefore needs to be reloaded upon completion of the action.  It also involves a web service call, which may rule out some solutions. 

After reading through the documentation and forums, I've found no good solutions, but concluded the following:

Why not use a list button with multi-select enabled?

This is my backup option, but it does not show the user that the intention is to select exactly one item from the list.  Additionally, some (Foo) items in the list may not be in the correct state to perform the action.  It would be nice if this information is displayed, instead of using errors to inform the user of an incorrect (Foo object) choice.

Why not use a formula field, with a URL?

Using a formula to create a column of URLs always opens a new window, which can't be hidden/closed.

Why not create a custom VisualForce page for the Foo list?
I have not found a way to set a VisualForce page to replace the default for a related list.  I have also not found a way to add a VisualForce page to the related lists section of a standard object (Case).

Assumptions:

The end goal is to deliver an app which can integrate with existing organizations.  Therefore, replacing the detail view for the Case object is not an option, because this would make the extension difficult to integrate for organizations which are already using a different custom Case view.