Haven't found a fix, but here's my workaround to prevent forms from being inadvertantly hidden if the NavigateTo doesn't "take."
Code:
DoCmd.NavigateTo "acNavigationCategoryObjectType" 'Try to select Navigation Pane
If Len(Application.CurrentObjectName) = 0 Then' make sure it hasn't selected something else... like a form.
' This still could hide the wrong thing, but I don't want to resort to an API call to verify.
DoCmd.RunCommand acCmdWindowHide 'Hide selected.
ElseDebug.Print "Hide navigation bar tried to hide " & Application.CurrentObjectName & " at " & Now
End If