What to use for a map editor?

[NGen]

Hamsterman: Not quite. It depends on what functions you have called prior. If a GLRC hasn't been created then calls to those functions won't make any difference, and if you try to call some SFML functions afterwards you might end up with weird results because of how SFML might have expected a specific feature to be enabled or disabled, or maybe it expected the viewport to be a specific size, it could be a variety of things. Just make sure you read the source for the graphics library so you know what each function actually does, and so you don't go messing anything up.