with a minor refactoring of the actual resize function:
--8<---------------cut here---------------start------------->8---
(defcommand (esf-resize-window float-group) (dw dh)
((:number "dW = ") (:number "dH = "))
(let* ((window (current-window))
(parent (window-parent window))
(w (xlib:drawable-width parent))
;; get actual height: ignore title bar
(h (- (xlib:drawable-height parent) *float-window-title-height*)))
(float-window-move-resize window
:width (+ w dw)
:height (+ h dh))))
--8<---------------cut here---------------end--------------->8---
--
Eric S Fraga via gnus (Emacs 29.0.50 2022-08-16) on Debian 11.4
