Visual Studio Code 1.3 not only adds a passel of feature improvements and bug fixes, it shows Microsoft using a clean product slate to experiment. Microsoft is free to do things with Code that would be unwelcome and jarring in the full-blown Visual Studio environment.
Some new features are taken straight from the Visual Studio product. With Tabs, for instance, open files appear in a list of tabs along the top of the editor and can be reorganized by simply dragging and dropping. Users of Visual Studio and many other IDEs will find it a more familiar interface paradigm than the list of working files that showed up in the Explorer column to the right.
That working files list, by the way, has also changed; it's been replaced with an Open editors view that shows editors grouped in "stacks." Three stacks -- left, right, and center -- can be open at any one time, each with its own tabs and controls for managing items en masse (save all, close all, and so on). It's a fairly dramatic change from previous versions of Code, so Microsoft has provided options to switch back to the old behaviors should people prefer.
Other improvements amount to controlled UI/UX experiments. Preview editors, for instance, let you see the contents of a file without actually opening it. Single-clicking a file name in Code's Explorer pops open a tab that shows the contents of the file; subsequent single clicks on other files reuse the same tab for file previews. If you start editing the file in place, the tab turns into a full-blown editor tab. It's a good way to reduce the amount of tab clutter that often accumulates during a busy session.
Some improvements don't change or rethink what was already there so much as polish it. Visual Studio Code has already accumulated an impressive gallery of third-party extensions for popular programming languages and syntaxes, but figuring out what was already installed or needed revising was no simple matter. A revised extension manager for Code streamlines the process of adding, changing, or updating extensions; it's much easier to read and sort through as well.
Finally, Microsoft hasn't forgotten to include features that people actually requested. There's now a powerful global search and replace tool -- which most IDEs need. Changes can be previewed, applied selectively, and examined with the built-in Diff tool. It's likely that Code's origins as a one-file-at-a-time editor, rather than a project-oriented IDE, are the reason global search and replace weren't there originally. But it's impossible to ignore that Code is used now as much for working with multiple files in a project as for one-off editing.
Microsoft would have made a profound mistake if it had tried to gradually transform Visual Studio Code into a recapitulation of Visual Studio. A lot of what's in Visual Studio is also worth having in Visual Studio Code, and so far Microsoft has been judicious about adding pieces that would be welcome. But the real value of Code is that it provides a playground for building a developer's environment that doesn't necessarily owe anything to the existing Microsoft toolset.