CtrlShiftI is very cool, but I find some questions when using Simple UML plugin.
If we implement a custom FileEditor, and we can open some custom file types. I think CtrlShiftI can also work. But when we invoke CtrlShiftI in the editor, and IDEA give us a thumbnail for custom file types. But when we click "edit source" in the thumbnail, IDEA will give us message: "file has been opened" for custom FileEditor.
I think IDEA should resolve this question.