I have read your question over and over trying to understand as I can leave mine overnight and it doesn't lose button configuration. Once a Devise/Activity is lit green it stays that way till either Off is pressed or another Device/Activity is pressed. The only thing I can come up with, as you mention “shows the device list”, is you are expecting buttons from an Activity to still be active in Device Mode, if so they don’t and it is nothing to do with the screen timing out. Please explain a bit more.