Bug 80429 [Preferences] [Dialogs] FieldEditors should relax requirements to support DialogPages
bundles/org.eclipse.jface/src/org/eclipse/jface/preference/FieldEditorPreferencePage.java
FieldEditor pe = (FieldEditor) e.next();
                result = Math.max(result, pe.getNumberOfControls());
            }
        }
        return result;
    }
    /**
     * Recomputes the page's error state by calling <code>isValid</code> for
     * every field editor.
     */
    protected void checkState() {
        boolean valid = true;
        invalidFieldEditor = null;
        
        
        if (fields != null) {
            int size = fields.size();
            for (int i = 0; i < size; i++) {
                FieldEditor editor = (FieldEditor) fields.get(i);
                valid = valid && editor.isValid();
                if (!valid) {
                    invalidFieldEditor = editor;
                    break;
                }
            }
        }
        setValid(valid);
    }
    /* (non-Javadoc)
     * Method declared on PreferencePage.