That is not a very surprising assumption. It is logical to assume that you should consider building your Swing application on the NetBeans Platform if you're thinking about creating "some kind of editor". But it shows a misunderstanding of what the NetBeans Platform is. The NetBeans Platform is not bits and pieces removed from NetBeans IDE. Quite the opposite, in fact: NetBeans IDE is bits and pieces placed on top of the NetBeans Platform! I.e., the relationship is the other way round: the NetBeans Platform is the dominant partner, while the NetBeans IDE is just one way (of many) in which the NetBeans Platform can be used.
However, of course, when it comes to talking about how something "looks", one shouldn't be using words. One should be using pictures. So here are three applications on top of the NetBeans Platform:
None of them look like any kind of IDE. Say about them whatever you like, but you can't say: "Wow, those look a lot like NetBeans IDE". The only thing the above have in common with NetBeans IDE is their infrastructure, not "the way they look". Many more screenshots (and more are being added all the time) can be found here.