From 24414f6189c87520163825db1d7d7ebbe474c6ad Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Fri, 27 Mar 2026 05:25:06 +0000
Subject: [PATCH 1/2] Fix scrollbar hit region to account for window margin
 (issue #9756)

Agent-Logs-Url: https://github.com/kovidgoyal/kitty/sessions/eb5869d6-9938-4ff3-87fb-34fe14694d6c

Co-authored-by: kovidgoyal <1308621+kovidgoyal@users.noreply.github.com>
---
 docs/changelog.rst |  2 ++
 kitty/mouse.c      | 12 ++++++++++++
 2 files changed, 14 insertions(+)

diff --git a/docs/changelog.rst b/docs/changelog.rst
index 52010cbff..554a1af8c 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -188,6 +188,8 @@ Detailed list of changes
 
 - Fix a spurious mouse button release event being sent when dragging out of an OS window causes focus loss
 
+- Fix scrollbar hover/interaction not working when the scrollbar is drawn in the window margin area (:iss:`9756`)
+
 0.46.2 [2026-03-21]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
diff --git a/kitty/mouse.c b/kitty/mouse.c
index a80375cd1..58da819aa 100644
--- a/kitty/mouse.c
+++ b/kitty/mouse.c
@@ -1012,6 +1012,18 @@ mouse_region(bool detect_borders, bool detect_title_bar) {
                 }
             }
         }
+        // If no window was found via contains_mouse, check if the mouse is in any
+        // window's scrollbar hit area. The scrollbar may be drawn in the margin
+        // which is outside the area covered by contains_mouse.
+        if (!ans.window && OPT(scrollbar_interactive)) {
+            for (unsigned int i = 0; i < t->num_windows; i++) {
+                Window *win = t->windows + i;
+                if (!win->visible || !win->render_data.screen) continue;
+                if (get_scrollbar_hit_type(win, w->mouse_x, w->mouse_y) != SCROLLBAR_HIT_NONE) {
+                    ans.window_idx = i; ans.window = win; break;
+                }
+            }
+        }
     }
     return ans;
 }

From df79b8247f23eff0d519e0bf3b8b8dffe8b60682 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Fri, 27 Mar 2026 05:48:50 +0000
Subject: [PATCH 2/2] Give hovered scrollbar precedence over window borders to
 prevent flickering

Agent-Logs-Url: https://github.com/kovidgoyal/kitty/sessions/260f17ab-b8d3-4581-ae88-de6f6c011637

Co-authored-by: kovidgoyal <1308621+kovidgoyal@users.noreply.github.com>
---
 kitty/mouse.c | 29 +++++++++++++++++++++++------
 1 file changed, 23 insertions(+), 6 deletions(-)

diff --git a/kitty/mouse.c b/kitty/mouse.c
index 58da819aa..f7533a873 100644
--- a/kitty/mouse.c
+++ b/kitty/mouse.c
@@ -986,15 +986,32 @@ mouse_region(bool detect_borders, bool detect_title_bar) {
                     window_id = closest_horiz->border_type < 0 ? -closest_horiz->border_type : closest_horiz->border_type;
             }
             if (ans.window_border) {
-                if (window_id) {
-                    for (unsigned int i = 0; i < t->num_windows; i++)
-                        if (t->windows[i].id == window_id) {
-                            ans.window = t->windows + i;
-                            ans.window_idx = i;
+                // If a hovered scrollbar overlaps this border region, the
+                // scrollbar takes precedence to avoid flickering when the
+                // expanded hover-width scrollbar straddles the border.
+                bool scrollbar_takes_precedence = false;
+                if (OPT(scrollbar_interactive)) {
+                    for (unsigned int i = 0; i < t->num_windows; i++) {
+                        Window *win = t->windows + i;
+                        if (!win->visible || !win->render_data.screen) continue;
+                        if (win->scrollbar.is_hovering && get_scrollbar_hit_type(win, w->mouse_x, w->mouse_y) != SCROLLBAR_HIT_NONE) {
+                            scrollbar_takes_precedence = true;
                             break;
                         }
+                    }
                 }
-                return ans;
+                if (!scrollbar_takes_precedence) {
+                    if (window_id) {
+                        for (unsigned int i = 0; i < t->num_windows; i++)
+                            if (t->windows[i].id == window_id) {
+                                ans.window = t->windows + i;
+                                ans.window_idx = i;
+                                break;
+                            }
+                    }
+                    return ans;
+                }
+                ans.window_border = 0;
             }
         }
         for (unsigned int i = 0; i < t->num_windows; i++) {