To display the limits of the controls in a window or dialog box as they might appear on a different display type, select the Show control limits button on the toolbar. Double left-clicking the button on the toolbar will display Dialog Unit Definition dialog box, in which you can define the different display types for testing the controls.
You select the target device from the Device drop-down list box. The selection of an item in the list will cause the fields in the dialog box to display the number of colors for the device, along with its horizontal and vertical resolution. The dialog box factors will also be displayed.
The dialog box factors for the device you are currently using, as well as the factors from the target device, will be used as part of the ratio determination. You will be able to see by selecting the Show control limits button on the toolbar, the display limits of the controls as they might be created on that particular device.
Even though this will display the limits of the controls for given devices, you should still test the application against that device, because the display limits are only an approximation of what the limits might be. There are no definitive methods of converting the limits of the controls from one device to another.