Bridge > Filter > File Type does not find PSDs in sub-folders; it only finds PSDs in the selected folder. This is a useless search that adds zero value for users; I can find this faster simply by opening the folder.
Think of the use case through the following scenario. It's dinner time and you're looking for your kids who are somewhere in the neighbourhood. If you search for them with a drone unit, you can find them if they are playing outside. But if they are inside their friends' homes playing video games, this search is useless. What you really need is to be able to find your kids whether they're outside all the homes (parent folder results) or both outside and inside neighbours' homes (parent and child folders).
This is the same as the use case search scenario most of us have most of the time when we search Bridge: "Where the heck did I save PSD x or PSD y?" Therefore, please set the Bridge > Filter > File Type search function to display all PSD files that exist in the selected folder as well as in all of the sub-folders.
Windows Explorer can almost do this. It can find all the files of a type or name content, but it does not show the thumbnails of Adobe files. Seeing the thumbnail in the search results is what makes Bridge so useful. So, being able to scan all the thumbnails of a file type in the parent folder and all its sub-folders helps me find what I'm looking for.
Please add this functionality.