We’re big Plex & Roku users in the house, and recently I installed Weather4Us which runs as the Roku screen saver so any time the device goes idle, you get the weather report cycling on screen. The problem is, it doesn’t work if the Plex app is running.
The issue appears to be a Roku bug (or unintended feature). If an application has a screen saver entry point, it will only fall back to the actual Roku default (out of the box) screen saver, not the currently selected screen saver. The work around is basically to delete the entry point.
Because the Plex Roku client is Open Source, and on github, I created my own branch with this one change. And I’ve uploaded it to the Roku store as a private channel called PlexNoSS. Feel free to install if you want this change. I’m going to be using this as my main plex install, so I’ll keep try to keep current on the plex client changes, but realize their might be a lag.