I am pretty new to Sketch. I am currently trying to merge two shapes into a single one. However whenever I hit "union" it does "merge" them, though basically they are still separate paths, that are just grouped together:
Well, should've spent more time on the official website ...
When you flatten a shape in Sketch, it will try to represent the multiple paths inside the shape as one path; it will, so to speak, ‘flatten’ the hierarchy. However there are many paths that can’t be flattened into one. A shape with a hole inside it will always have to be represented as two paths; one for outer path, and one for the inner path.
When Sketch cannot flatten a path it will warn when you try to do so. If you persist, the subpaths you had will be replaced by different subpaths.
If you’re used to other design tools, you may automatically look to flatten a path after you have applied a boolean operation. In Sketch there’s no need for that; you can apply as many boolean operations on top of one-another keeping each subpath independent and editable.