Does ubuntu work on the 4k display?
I'm planning to buy lenovo thinkpad laptop with 4k screen. But I have concern about whether scaling works as expected or not.
Gnome Shell has very good HDPI support, and so do more recent programs that use modern toolkits (GTK3 and up, QT4 and up). All the applications installed by default will play well with HDPI.
Linux, however, is a very diverse ecosystem. There might be programs that want to install which do not play well with HiDPI. For example, the bitmap editing application Gimp, is still using GTK2, and plays somewhat less well on HiDPI, although themes with large icons are foreseen to counter usability issues.
Gnome Shell has very good HDPI support, and so do more recent programs that use modern toolkits (GTK3 and up, QT4 and up). All the applications installed by default will play well with HDPI.
Linux, however, is a very diverse ecosystem. There might be programs that want to install which do not play well with HiDPI. For example, the bitmap editing application Gimp, is still using GTK2, and plays somewhat less well on HiDPI, although themes with large icons are foreseen to counter usability issues.