When using custom tags with custom attributes of type "link", when you open the custom tag popup window, there will be three buttons, "Search", "Browse" and "Bookmarks". If the custom tag you created has underscores in its name, when you click in any of those buttons, you will be re-directed to an empty "Properties" area (see screenshot).
This will not occur if the custom tag name has no underscores.
1. Create a custom tag that contains a custom attribute of type "link". Called it "stvd_button". Use attached "content.ini.append.php" and "ezoe_attributes.ini.append.php" files as reference;
2. Create or edit a content that contains an XML block field (used Article/Body);
3. On the XML block field, click "Insert custom tag" button;
4. Select "stvd_button" custom tag;
5. Click on either "Search", "Browse" or "Bookmarks" button. You will be re-directed to an empty "Properties" area (see screenshots).