Capturing menus
1. Single menu
The easiest way to capture a single menu is to use Snapper in window mode. A menu is a wimp window of specific layout. Simply raise the menu by clicking the mouse menu button, leave the mouse over the menu, and then use the trigger key combination to snap the menu. See the next page for some screen shots of single menu capture, which show the effect of the pointer settings in the control window.
2. Full menu structure
A full menu structure with submenus or dialogue boxes is constructed from more than one window, and cannot be captured in one shot while in window mode. You have two choices. Firstly you can use window mode to capture the main menu and each of the submenus in turn, and then use other software to stick the component parts back together again.
Secondly, you can use the area mode to capture the whole menu in one shot. This would normally require a dummy run in order to size and position the snap area to enclose the menu. Once satisfied, raise the menu again, and use the trigger key combination to grab the menu. You might end up with something similar to that shown below.

This may be suitable in some cases, but the image shows the background window(s) and desktop backdrop, which may be distracting.
Using Fill
Here is where the Fill option comes in. The snap shown above was taken with the default fill of Trans (transparent) so everything within the snap area is shown. If we set the fill to a colour, in this case I have used light blue to contrast with the white html page background, then we get the snap shown below, which is much cleaner. The only difference in obtaining these two snaps was in the fill setting. The two images are exactly the same size, and the menu was opened as near as possible to the same place in the two cases. To eliminate the large border, either position the snap area and menu structure more accurately, or use image processing software to crop the final image. Normally, the fill colour would be chosen to be the same as the background over which the image was to be shown - on this page, for example, white would be used.

For the technically minded, here is a brief explanation, which shows the power of David's program. The red area borders are made up of a total of eight separate wimp windows, corresponding to the sides and corners of the area. Thus there is nothing owned by Snapper within the delineated area, so it is normally transparent, and the desktop can be seen through. A snap under these conditions will capture everything visible, as in the first shot above. If you have been moving/resizing the area using the Select mouse button then the red border will be at the top of the window stack i.e. in front of all the other windows. When a menu is first opened it is always shown in front of (on top of) all the other windows, so it will be in front of the border. If a snap is now taken with Fill set to a colour, Snapper temporarily creates a new blank window (with no window furniture) within the snap area with a background colour set to the fill colour and at a level in the window stack corresponding to the area red border position. In this particular case only the menu will be still visible because it is in front of the area red border. The snap is now taken showing the menu against the plain colour background (second shot). Then the temporary fill window is deleted and the border area is once again transparent.