If you ask me, this will cause more distraction than being productive. In your example, would Slack be needed all the time, so it would worth keeping a quarter of the screen? Then IDEs for example have a lot of menus, panes, buttons and everything. You would have much less space for the actual code if you not have it in full screen mode. It might be personal style, but I find having 3 full screen windows and swtiching between them (with the most used, browser, in the middle) with a quick swipe is the most productive.