Based on the latest Unity 3D 5.3.1 game engine, the new Unity Editor for Linux version brings various improvements for things like web view integration, including docking, focus and resizing, as well as mouse cursor position reporting in the game view.
Additionally, Unity Editor for Linux 5.3.1 also adds some improvements to the OpenGL legacy mode, along with fixes for issues with arrows keypresses in the game view, which changed the keyboard focus, and the “Add Resolution” pop-up for the game view.