What is claimed is:1. A non-transitory computer-readable storage medium storing a set of device control program instructions installed on and executed by a computer of a data processing apparatus, the data processing apparatus including the computer, an input interface, a storage, and a display, the set of device control program instructions, when executed by the computer, causing the data processing apparatus to perform:receiving a first selection of either one of a first function and a second function through the input interface;receiving, through the input interface, a selection of a device for executing the function selected by the first selection;storing, in the storage, device data of the device selected for executing the function selected by the first selection;after storing the device data of the selected device, receiving a second selection of either one of the first function and the second function through the input interface; anddisplaying, on the display, a screen including an image for receiving an instruction to execute the function selected by the second selection,wherein in a case where the function selected by the second selection is the same as the function selected by the first selection, the screen further includes the stored device data as indicative of a device for executing the function selected by the second selection; andwherein in a case where the function selected by the second selection is different from the function selected by the first selection, the screen further includes the stored device data as indicative of the device for executing the function selected by the second selection.2. The non-transitory computer-readable storage medium according to claim 1, wherein in a case where the function selected by the second selection is different from the function selected by the first selection and the selected device has both of the first function and the second function, the screen includes the stored device data as indicative of the device for executing the function selected by the second selection.3. The non-transitory computer-readable storage medium according to claim 2, wherein the storing the device data includes:determining whether the selected device has both of the first function and the second function;in a case where the selected device has both of the first function and the second function, storing the device data of the selected device for each of the first function and the second function; andin a case where the selected device does not have a function other than the function selected by the first selection, storing the device data of the selected device for the function selected by the first selection but not for the function other than the function selected by the first selection.4. The non-transitory computer-readable storage medium according to claim 3, wherein the displaying the screen includes:determining whether device data of a device having the function selected by the second selection is already stored in the storage,in a case where the device data of the device having the function selected by the second selection is stored in the storage, displaying the screen such that the screen includes the stored device data of the device having the function selected by the second selection as the device for executing the function selected by the second selection, andin a case where no device data of a device having the function selected by the second selection is stored in the storage:performing a search for at least one device communicable with the data processing apparatus and having the function selected by the second selection;receiving, through the input interface, a selection of the device for executing the function selected by the second selection from among at least one device found in the searching;storing, in the storage, device data of the device selected for the function selected by the second selection; anddisplaying the screen such that the screen includes the device data of the device selected for the function selected by the second selection as the device for executing the function selected by the second selection.5. The non-transitory computer-readable storage medium according to claim 4, wherein the set of device control program instructions, when executed by the computer, cause the data processing apparatus to further perform:in a case where the first selection is received, searching for at least one device communicable with the data processing apparatus and having the function selected by the first selection, andwherein the selection of the device for executing the function selected by the first selection is from among at least one device found in the searching.6. The non-transitory computer-readable storage medium according to claim 5, wherein the set of device control program instructions, when executed by the computer, cause the data processing apparatus to further perform:receiving, from the selected device, information of one or more functions which the selected device possesses, andwherein the determining whether the selected device has both of the first function and the second function is based on the received information.7. The non-transitory computer-readable storage medium according to claim 1, whereinin a case where the storage already stores device data of another device which is different from the selected device, the storing stores the device data of the selected device in addition to the device data of the another device in the storage, and the displaying displays the screen such that the screen includes the stored device data of the selected device as indicative of the device for executing the function selected by the second selection, in addition to the image for receiving the instruction to execute the function selected by the second selection.8. The non-transitory computer-readable storage medium according to claim 7, wherein the screen further includes an image for receiving an instruction to change the device for executing the function selected by the second selection, from the selected device to the another device.9. The non-transitory computer-readable storage medium according to claim 1, wherein the first function is a printer function, and the second function is a scanner function.10. A data processing apparatus comprising:an input interface;a storage;a display; anda control device configured to perform:receiving a first selection of either one of a first function and a second function through the input interface;receiving, through the input interface, a selection of a device for executing the function selected by the first selection;storing, in the storage, device data of the device selected for executing the function selected by the first selection;after storing the device data of the selected device, receiving a second selection of either one of the first function and the second function through the input interface; anddisplaying, on the display, a screen including an image for receiving an instruction to execute the function selected by the second selection,wherein in a case where the function selected by the second selection is the same as the function selected by the first selection, the screen further includes the stored device data as indicative of a device for executing the function selected by the second selection; andwherein in a case where the function selected by the second selection is different from the function selected by the first selection, the screen further includes the stored device data as indicative of the device for executing the function selected by the second selection.11. A method for controlling a data processing apparatus, the data processing apparatus including an input interface, a storage, and a display, the method comprising:receiving a first selection of either one of a first function and a second function through the input interface;receiving, through the input interface, a selection of a device for executing the function selected by the first selection;storing, in the storage, device data of the device selected for executing the function selected by the first selection;after storing the device data of the selected device, receiving a second selection of either one of the first function and the second function through the input interface; anddisplaying, on the display, a screen including an image for receiving an instruction to execute the function selected by the second selection,wherein in a case where the function selected by the second selection is the same as the function selected by the first selection, the screen further includes the stored device data as indicative of a device for executing the function selected by the second selection; andwherein in a case where the function selected by the second selection is different from the function selected by the first selection, the screen further includes the stored device data as indicative of the device for executing the function selected by the second selection.