From 5ea45919d7090a1fd3f77fe75eaddd97fd54f3bd Mon Sep 17 00:00:00 2001
From: 00jciv00 <jake.crawfordiv@gmail.com>
Date: Thu, 7 May 2026 15:11:33 -0400
Subject: [PATCH 1/2] config: add gtk-horizontal-tab-scroll option

Add a boolean config option to enable/disable two-finger horizontal
touchpad scrolling for switching tabs. Defaults to true to preserve
existing behavior.

When tab scrolling is disabled or the scroll source is not a touchpad,
forward horizontal scroll events to the terminal so applications like
neovim can handle them.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 src/apprt/gtk/class/surface.zig | 63 +++++++++++++++++++++------------
 src/config/Config.zig           |  6 ++++
 2 files changed, 47 insertions(+), 22 deletions(-)

diff --git a/src/apprt/gtk/class/surface.zig b/src/apprt/gtk/class/surface.zig
index 179c779d7..c101892de 100644
--- a/src/apprt/gtk/class/surface.zig
+++ b/src/apprt/gtk/class/surface.zig
@@ -2984,37 +2984,56 @@ pub const Surface = extern struct {
     ) callconv(.c) c_int {
         const priv: *Private = self.private();
 
-        switch (ec.getUnit()) {
-            .surface => {},
-            .wheel => return @intFromBool(false),
-            else => return @intFromBool(false),
-        }
+        // Check if horizontal tab scrolling is enabled and this is a
+        // touchpad surface scroll. If not, forward to the terminal.
+        const tab_scroll_enabled = if (priv.config) |config|
+            config.get().@"gtk-horizontal-tab-scroll"
+        else
+            true;
 
-        priv.pending_horizontal_scroll += x;
+        const is_surface_scroll = ec.getUnit() == .surface;
+
+        if (tab_scroll_enabled and is_surface_scroll) {
+            priv.pending_horizontal_scroll += x;
+
+            if (@abs(priv.pending_horizontal_scroll) < 120) {
+                if (priv.pending_horizontal_scroll_reset) |v| {
+                    _ = glib.Source.remove(v);
+                    priv.pending_horizontal_scroll_reset = null;
+                }
+                priv.pending_horizontal_scroll_reset = glib.timeoutAdd(500, ecMouseScrollHorizontalReset, self);
+                return @intFromBool(true);
+            }
+
+            _ = self.as(gtk.Widget).activateAction(
+                if (priv.pending_horizontal_scroll < 0.0)
+                    "tab.next-page"
+                else
+                    "tab.previous-page",
+                null,
+            );
 
-        if (@abs(priv.pending_horizontal_scroll) < 120) {
             if (priv.pending_horizontal_scroll_reset) |v| {
                 _ = glib.Source.remove(v);
                 priv.pending_horizontal_scroll_reset = null;
             }
-            priv.pending_horizontal_scroll_reset = glib.timeoutAdd(500, ecMouseScrollHorizontalReset, self);
+
+            priv.pending_horizontal_scroll = 0.0;
+
             return @intFromBool(true);
         }
 
-        _ = self.as(gtk.Widget).activateAction(
-            if (priv.pending_horizontal_scroll < 0.0)
-                "tab.next-page"
-            else
-                "tab.previous-page",
-            null,
-        );
-
-        if (priv.pending_horizontal_scroll_reset) |v| {
-            _ = glib.Source.remove(v);
-            priv.pending_horizontal_scroll_reset = null;
-        }
-
-        priv.pending_horizontal_scroll = 0.0;
+        // Forward horizontal scroll to the terminal (e.g. for neovim).
+        const surface = priv.core_surface orelse return @intFromBool(false);
+        const scaled = self.scaledCoordinates(x, 0);
+        surface.scrollCallback(
+            scaled.x * -1,
+            0,
+            .{},
+        ) catch |err| {
+            log.warn("error in scroll callback err={}", .{err});
+            return @intFromBool(false);
+        };
 
         return @intFromBool(true);
     }
diff --git a/src/config/Config.zig b/src/config/Config.zig
index 5b1d73deb..f803ca12d 100644
--- a/src/config/Config.zig
+++ b/src/config/Config.zig
@@ -3649,6 +3649,12 @@ else
 /// which is the old style.
 @"gtk-wide-tabs": bool = true,
 
+/// If `true` (default), then two-finger horizontal scrolling on a touchpad
+/// will switch between tabs. Scrolling left goes to the next tab and
+/// scrolling right goes to the previous tab. Set this to `false` to
+/// disable this behavior.
+@"gtk-horizontal-tab-scroll": bool = true,
+
 /// Custom CSS files to be loaded.
 ///
 /// GTK CSS documentation can be found at the following links:

From b5f5ca07892f4df799bcc4645f80e441640b5946 Mon Sep 17 00:00:00 2001
From: "Jeffrey C. Ollie" <jeff@ocjtech.us>
Date: Sun, 17 May 2026 21:12:51 -0500
Subject: [PATCH 2/2] Add "available since"

---
 src/config/Config.zig | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/config/Config.zig b/src/config/Config.zig
index f803ca12d..cb1964010 100644
--- a/src/config/Config.zig
+++ b/src/config/Config.zig
@@ -3653,6 +3653,8 @@ else
 /// will switch between tabs. Scrolling left goes to the next tab and
 /// scrolling right goes to the previous tab. Set this to `false` to
 /// disable this behavior.
+///
+/// Available since 1.4.0.
 @"gtk-horizontal-tab-scroll": bool = true,
 
 /// Custom CSS files to be loaded.