When I create composite glyph in Font Creator version 2885, the RSB value is shown in the AW section. I think there is an issue in the program.
It is intended to work this way.
base(glyphname,master)
It provides a value that syncs the specific metric (side-bearing, aw, or, ah) of the specified glyph. If you don’t provide a glyphname, it assumes the current glyph for empty and simple glyphs, and it assumes the first glyph member for composite glyphs. This is especially useful for composite glyphs that have accents that go out of bounds of the base glyph. The function does not require a glyph name, which makes it even more convenient.
Previous releases did set base() to both LSB and RSB, but that occasionally caused a rounding error on exporting a font, as then the LSB and AW are stored.
Thank you.