12. In a computing environment, a system, comprising: one or more stores that include a registry that includes one or more entries, the entries associating file extensions with designer packages; a designer package that includes a designer factory that references one or more designer providers, the one or more designer providers operable to determine whether one or more designers of a plurality of designers support a file having an extension, the designer factory operable to create a control that includes the one or more designers in response to determining that the one or more designers support the file having the extension; a registry manager operable to receive an indication of the designer package together with an indication that the designer package is to be associated with all extensions, the registry manager further operable to create an entry within the registry that associates the designer package with the all extensions; and a designer manager operable to receive a request to edit an indicated file having an indicated extension, to determine the designer package using the registry manager, and to call the designer factory to create the control that includes the one or more designers that support the indicated file in response to a determination that the one or more designers support the indicated file, the designer factory being configured to return a code that indicates that the designer factory is unable to find the one or more designers in response to a determination that the one or more designers do not support the indicated file.
12. In a computing environment, a system, comprising: one or more stores that include a registry that includes one or more entries, the entries associating file extensions with designer packages; a designer package that includes a designer factory that references one or more designer providers, the one or more designer providers operable to determine whether one or more designers of a plurality of designers support a file having an extension, the designer factory operable to create a control that includes the one or more designers in response to determining that the one or more designers support the file having the extension; a registry manager operable to receive an indication of the designer package together with an indication that the designer package is to be associated with all extensions, the registry manager further operable to create an entry within the registry that associates the designer package with the all extensions; and a designer manager operable to receive a request to edit an indicated file having an indicated extension, to determine the designer package using the registry manager, and to call the designer factory to create the control that includes the one or more designers that support the indicated file in response to a determination that the one or more designers support the indicated file, the designer factory being configured to return a code that indicates that the designer factory is unable to find the one or more designers in response to a determination that the one or more designers do not support the indicated file. 14. The system of claim 12 , wherein the designer factory being operable to create a control that includes the one or more designers comprises the designer factory being operable to create a control that includes a tab element for each of the one or more designers, the tab element operable to receive a command to switch to a designer associated with the tab element.