I first reported this issue ages ago but still no fix. This should be the easiest of things for Samsung to fix so i can only assume it's not been addressed at all.
To be clear what I'm referring to: the built-in inter-app file browser I'm referring to is the browser which appears to allow you to pick a file on your tablet to import into the app you're currently using (it is clearly an inbuilt feature as some apps use their own browser for this purpose and they are always obviously different from this default one). Clicking on a file within this default browser can only be done with a finger tap, it doesn't respond to the s-pen. Can Samsung please fix this in an update?
To check this for yourself, open Samsung Notes and import an image. When asked to choose the app to use to browse for your image, choose the 'Files' app with the blue icon (not 'My Files' with the yellow icon). Then, the browser shown will be unresponsive to the S-pen and you'll have to use your finger to pick an image to import.
Please note: not all apps give you the option of which file browser to use to import files (as Samsung Notes does) but automatically use this Files app, hence why this is a problem. Snapseed for example.
Hopefully this can be reported to the relevant department and be fixed. Thanks.