Prevent errant scroll on mouse click (Bug#31546)

* src/nsterm.m (ns_mouse_position): Use correct frame when determining
  mouse position.
* lisp/mouse.el (mouse-drag-track): Only account for mode-line height
  if `mode-line-format' is non-nil.

1 files changed, 5 insertions, 1 deletions

diff --git a/lisp/mouse.el b/lisp/mouse.el
index 9a3e2235ece..5c9056fb43d 100644
--- a/lisp/mouse.el
+++ b/lisp/mouse.el
@@ -1225,7 +1225,11 @@ The region will be defined with mark and point."
          (bounds (window-edges start-window))
          (make-cursor-line-fully-visible nil)
          (top (nth 1 bounds))
-         (bottom (if (window-minibuffer-p start-window)
+         (bottom (if (or (window-minibuffer-p start-window)
+                         ;; Do not account for the mode line if there
+                         ;; is no mode line, which is common for child
+                         ;; frames.
+                         (not mode-line-format))
                      (nth 3 bounds)
                    ;; Don't count the mode line.
                    (1- (nth 3 bounds))))