From 895afe00e1e8b8a39599c308115ce7d1644ad94b Mon Sep 17 00:00:00 2001
From: "Matt A. Tobin" <email@mattatobin.com>
Date: Mon, 12 Jul 2021 12:58:30 -0400
Subject: [PATCH] Issue #1793 - Add a border-bottom to treecols header

---
 toolkit/themes/windows/global/tree.css | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/toolkit/themes/windows/global/tree.css b/toolkit/themes/windows/global/tree.css
index 1300968248..ee176296b2 100644
--- a/toolkit/themes/windows/global/tree.css
+++ b/toolkit/themes/windows/global/tree.css
@@ -198,6 +198,14 @@ treechildren::-moz-tree-cell-text(progressmeter) {
 
 /* ::::: tree columns ::::: */
 
+@media (-moz-os-version: windows-win10) and (-moz-windows-theme: aero) {
+  treecols {
+    /* Windows 10's "aero" msstyle does not provide a complete style for
+       the treecols header so we need to provide a bottom border */
+    border-bottom: 1px solid ThreeDLightShadow;
+  }
+}
+
 treecol,
 treecolpicker {
   -moz-appearance: treeheadercell;