ChessGUI 0.180 is out there.

[Elorejano]

Hi, Mathias!
Thanks for your replay!
Gui book Impementation must be fixed but even improved like a dialog box only for opening books for uci engines, IMHO.
Thanks again

[Matthias Gemuh]

Hi, Mathias!
Thanks for your replay!
Gui book Impementation must be fixed but even improved like a dialog box only for opening books for uci engines, IMHO.
Thanks again

Why do you want to handle GUI book differently for UCI and WB ?

1) to borrow main book, just click "Borrow main GUI Book".
2) to use private book, click "has private GUI Book" and choose the book in "Eng Options 2"/"Edit Engine parameters".

I tested both options and they always work, though first move of White is not yet played from book.

Matthias