Jean,
I was looking to experiment with mitering the front edge of the side but it seems that you can do that only with face frame cabinets.
I believe you may be refering to the setting: "
ANGLED FRONT FACE FRAME SETTING - Left and Right Sides Mitered [ ]". If I am not mistaken, this setting in fact deals with mitering of the face frame stile components and not the actual ends.
I am not a cabinetmaker, but I have seen a few (read very few) clients that do miter that front edge. As far as I know, most would simply angle the blade and trim that front edge off on the table saw.
This automatic allowance for the "Mitered Front Edge" on an angular corner cabinet is similar to the automatic mitered center-back allowances that eCab performs. A nice function, if you use it - an issue to workaround if you do not. The "Mitered Center Back" switch was introduced in V6 and allows you to turn this added allowance off and have eCab simply "butt" the center-back against the left and right back components.
What now would be nice is a "Mitered Front Edge" switch on both the left and right end components (on centrally in the CORNER SETTINGS tab) for corner cabinets. This would eliminate the manual shortening and resizing when not mitering the front edges and would handle material changes automatically. (** Remember that the manual adjustments that you make to the left and right end depths are material thickness specific and have to be redone for materials of different thickness.)