From 0c213398f46116a9ab9c3c28e71a6143d4611c63 Mon Sep 17 00:00:00 2001 From: Piro / YUKI Hiroshi Date: Sat, 13 Feb 2016 01:52:30 +0900 Subject: [PATCH] Describe why we don't use the actual width of the scrollbar directly --- modules/utils.js | 3 +++ 1 file changed, 3 insertions(+) diff --git a/modules/utils.js b/modules/utils.js index dae000ff..24d02348 100644 --- a/modules/utils.js +++ b/modules/utils.js @@ -519,6 +519,9 @@ var TreeStyleTabUtils = { var scrollbox = aTabBrowser.tabContainer.mTabstrip._scrollbox; var d = scrollbox.ownerDocument; + // We have to calculate the width of the scroll bar indirectly + // based on the width of the container and the scrollable contents, + // because the scrollbar is not accessible via public APIs. var scrollbarSize = this.lastOriginalScrollbarSize; if (scrollbarSize == 0) { let nodes = d.getAnonymousNodes(scrollbox);