When you add multiple custom tags with attribute of type "link", only the last inserted works. For all the others an click on Search, Browse or Bookmarks has no effects at all.
Add 2 custom tags with an attribute of type "link", ie "testlink1" and "testlink2"
Create a content with an online editor and try to add a custom tag testlink1.
When you click on one of the buttons (Search content / Browse / Bookmarks) nothing happens
Change custom tag to "testlink2", now you can click on buttons Search content / Browse / Bookmarks and it works