fix: Various mobile fixes (#2295)

* fix: Input placeholder ellipsis

* fix: Hide scrollbar on nav tabs on mobile

* fix: Header actions should be fixed on mobile

* fix: Add fade when content in tabs does not fit in available horizontal width

app/components/Tabs.js

@@ -1,13 +1,39 @@
 // @flow
+import { transparentize } from "polished";
 import * as React from "react";
 import styled from "styled-components";
+import useWindowSize from "hooks/useWindowSize";
 
 const Nav = styled.nav`
   border-bottom: 1px solid ${(props) => props.theme.divider};
   margin: 12px 0;
   overflow-y: auto;
   white-space: nowrap;
-  transition: opacity 250ms ease-out;
+
+  -ms-overflow-style: none;
+  scrollbar-width: none;
+
+  &::-webkit-scrollbar {
+    display: none;
+  }
+
+  &:after {
+    content: "";
+    position: absolute;
+    top: 0;
+    right: 0;
+    width: 50px;
+    height: 100%;
+    pointer-events: none;
+    background: ${(props) =>
+      props.$shadowVisible
+        ? `linear-gradient(
+      90deg,
+      ${transparentize(1, props.theme.background)} 0%,
+      ${props.theme.background} 100%
+    )`
+        : `transparent`};
+  }
 `;
 
 // When sticky we need extra background coverage around the sides otherwise
@@ -30,10 +56,33 @@ export const Separator = styled.span`
   margin-top: 6px;
 `;
 
-const Tabs = (props: {}) => {
+const Tabs = ({ children }: {| children: React.Node |}) => {
+  const ref = React.useRef<?HTMLDivElement>();
+  const [shadowVisible, setShadow] = React.useState(false);
+  const { width } = useWindowSize();
+
+  const updateShadows = React.useCallback(() => {
+    const c = ref.current;
+    if (!c) return;
+
+    const scrollLeft = c.scrollLeft;
+    const wrapperWidth = c.scrollWidth - c.clientWidth;
+    const fade = !!(wrapperWidth - scrollLeft !== 0);
+
+    if (fade !== shadowVisible) {
+      setShadow(fade);
+    }
+  }, [shadowVisible]);
+
+  React.useEffect(() => {
+    updateShadows();
+  }, [width, updateShadows]);
+
   return (
     <Sticky>
-      <Nav {...props}></Nav>
+      <Nav ref={ref} onScroll={updateShadows} $shadowVisible={shadowVisible}>
+        {children}
+      </Nav>
     </Sticky>
   );
 };