The wallpaper test mode of the Contents Pane is used when you select a background (Background Image). If you actually paste a background image, it results in the copying of an image file that you may not require. In wallpaper test mode, a background can be selected quickly since an image is not copied and there is no need to drag and drop.
Setting wallpaper test mode
1. Display the image to be used for the wallpaper in the Contents Pane.
2. Right-click the contents display field and select [Wallpaper test mode].
3. Click the desired image.
=>An image selected as the background of the current HTML document appears.
Ending wallpaper test mode
1. Right-click the contents display field and select [Wallpaper test mode].
2. Click the current HTML document.
=>The background is undone.
Hint
When you actually want to paste an image as a background image, see [Paste as a background image] in Pasting an image.