If I remember correctly, selecting the file in the patcher just downloads a zip file to the DrumsUI\Alternatives folder; it doesn't actually install it. You would need to unzip that, rename the xml file by removing (HidableChatInput) from the file name, and then overwrite the originial file in the DrumsUI folder.
This is a late response and you may have figured it out already, but posting for others as well.
