Samsung made major changes to its DeX software experience last year. It brought a new user interface and also made away with some features users loved. One UI 8.5 brings back one of those features: the ability to automatically hide the taskbar.
One UI 8.5 returns the auto hide feature for the DeX taskbar
Samsung has gradually reintroduced some old DeX features after the software was lost after it experienced major changes. This includes the options for on-screen keyboard location, and to have the sound routed to the speakers in a connected display.

Samsung also brought back the auto hide taskbar toggle for DeX in the recent One UI 8.5 update for the Galaxy S26 series. To enable this DeX feature, head over to the Connected display menu for Samsung DeX in the Settings app. You’ll see the toggle available below the option for adjusting screen timeout settings.
With this option brought back, DeX users no longer have to worry about manually hiding the taskbar every time they go full-screen. Samsung also introduced an immersive mode with the revamped DeX last year when an app was redesigned, but the auto taskbar hide feature was downgraded.