DDS
DDS is a a highly extensible IDE made in D using dlangui for the interface. The primary design goal of DDS is to have complete extensibility, including within individual applications through plugin hooks. Applications will be able to use interfaces to provide IDE integration, such as toolbar items changing properties within your application when checked, clicking an in-game object to view it in a Properties window within the IDE, and more.
DDS is nowhere near being functional yet.