Any additions to the Server Launch Configuration's Classpath "User Entries" are lost when the dialog is closed and reopened.

This is likely related; there appears to be an issue where the initial values of "User Entries" are also incorrect (and are reverted from the "Restore Default Entries" value) when the dialog is reopened.
Specifically, the "org.jboss.ide.eclipse.as.core.server.launch.runJarContainer/JBoss 7.1 Runtime Server" library to a single external "jboss-modules.jar".

The attachments describe what happens:

• The initial state when editing the Launch Configuration is in JBIDE_1.png.
• When the "Restore Default Entries" button is clicked, the values are changed to what should be the default state (JBIDE_2.png).
• When the dialog is closed and reopened, it reverts back to the way it appeared in JBIDE_1.png.
• Similarly if I manually add an external directory (or any other entry, for that matter), as appears in JBIDE_3.png, after closing and reopening the dialog, it reverts back to the JBIDE_1.png state.

I've tried simply clicking "OK" and also making sure I click "Apply" before clicking "OK", but that doesn't seem to have an effect.

I've been able to replicate this on two separate (similarly configured) machines.

This sounds very similar to JBIDE-786, but that's very old and marked as Resolved a long time ago, so I figured it'd be appropriate to file a new issue.