Now as you know, input of DBCS requires more key-strokes than SBCS. Because of this, alphabetic characters are usually used as mnemonic characters although choices of action bars and pull-downs are translated to a national language.
DBCS PM provides an additional capability for mnemonics; it allows application developers (or maybe translators) to define two mnemonics. This function is implemented only in Japanese PM. The additional mnemonics are called alternate mnemonics and usually SBCS Katakana characters are assigned to them. Katakana characters are phonetic characters in Japanese like alphabets in your language. The user can select English or alternate mnemonics mode using PM control panel.
The alternate mnemonics are defined by a SBCS katakana character which is after the escape string "\37". For example, "D1D2D3D4(\036x\037y)" defines the "x" as the mnemonic and "y" as the alternate mnemonic of this string.
Note: The mnemonic belongs to the text that is included in a window control with selectable items, a pull-down menu or an action bar. Users can press the key, which create that mnemonic character, to select the item when this window control is focused. Because the DBCS keyboard shift status belongs to the frame window, it will not affect the key in character that is sent to the menu or the action bar control. So even the keyboard is in a different DBCS mode and creates a different character, users can still use the same key to select the mnemonic in a menu or an action bar window control.