Bug 88878 [Preferences] File and Content Type pages should link to one another
There should be some mention of the relationship between content type and file association pages.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/dialogs/ContentTypesPreferencePage.java
try {
                            if (spec.name != null) {
                                contentType.removeFileSpec(spec.name,
                                        IContentType.FILE_NAME_SPEC);
                            } else if (spec.ext != null) {
                                contentType.removeFileSpec(spec.ext,
                                        IContentType.FILE_EXTENSION_SPEC);
                            }
                        } catch (CoreException e) {
                            result.add(e.getStatus());
                        }
                    }
                    if (!result.isOK()) {
                        ErrorDialog.openError(event.widget.getDisplay()
                                .getActiveShell(), null, null, result);
                    }
                    fileAssociationViewer.setInput(contentType);
                }
            });
        }
    }
    protected Spec[] getSelectedSpecs() {
        List list = ((IStructuredSelection) fileAssociationViewer
                .getSelection()).toList();
        return (Spec[]) list.toArray(new Spec[list.size()]);
    }
    protected IContentType getSelectedContentType() {
        return (IContentType) ((IStructuredSelection) contentTypesViewer
                .getSelection()).getFirstElement();
    }