From 4aa1784ba37480584fbeb97a2934db86bf6dbd85 Mon Sep 17 00:00:00 2001
From: David Luzar <luzar.david@gmail.com>
Date: Sat, 2 May 2020 22:15:28 +0200
Subject: [PATCH] fix horizontal scroll via shift+wheel on mac (#1528)

---
 src/components/App.tsx | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/components/App.tsx b/src/components/App.tsx
index 0857ca52..38cfea3e 100644
--- a/src/components/App.tsx
+++ b/src/components/App.tsx
@@ -2570,7 +2570,8 @@ class App extends React.Component<any, AppState> {
     // scroll horizontally when shift pressed
     if (event.shiftKey) {
       this.setState(({ zoom, scrollX }) => ({
-        scrollX: normalizeScroll(scrollX - deltaY / zoom),
+        // on Mac, shift+wheel tends to result in deltaX
+        scrollX: normalizeScroll(scrollX - (deltaY || deltaX) / zoom),
       }));
       return;
     }