18. The method of claim 17 , further comprising exposing a previewer interface at the previewer, the previewer interface comprising: a load method for receiving an instruction to load the attached document to be visually previewed, a show method for displaying an instruction to show the visual preview of the attached document, and a window changed method for receiving an indication that the window in which the visual preview of the attached document is displayed has changed.
18. The method of claim 17 , further comprising exposing a previewer interface at the previewer, the previewer interface comprising: a load method for receiving an instruction to load the attached document to be visually previewed, a show method for displaying an instruction to show the visual preview of the attached document, and a window changed method for receiving an indication that the window in which the visual preview of the attached document is displayed has changed. 21. The method of claim 18 , wherein the window changed method on the previewer interface is called by the preview handler in response to receiving a call to the window changed method on the preview handler interface.