Features

I never understood, why Opera dropped concept of flexible tab-windows inside the main browser window.
Opera was my main browser for years on PC, I was able to have resizable/movable tabs + email + ICQ + RSS + notes in one browser window and it was running smoothly even on PC with only 256MB RAM.https://www.reddit.com/r/macapps/comments/oz66ra/after_9_months_i_am_finally_launching_sigmaos_a/