Bug 1388514 - Make the sidebar splitter narrower again to prevent it from overlapping the scrollbar too much, and disable this behavior on Linux since scrollbars are too narrow on Ubuntu. r=Gijs

MozReview-Commit-ID: Hi4MUsbEFXd

--HG--
extra : rebase_source : c7f6a15671e19ab1562e085fe3a200712aa81b3f

browser/themes/linux/browser.css

@@ -587,7 +587,11 @@ html|span.ac-emphasize-text-url {
 }
 
 .sidebar-splitter {
-  border-color: ThreeDShadow;
+  -moz-appearance: none;
+  width: 6px;
+  background-color: -moz-dialog;
+  border: 1px ThreeDShadow;
+  border-style: none solid;
 }
 
 .browserContainer > findbar {

browser/themes/shared/sidebar.inc.css

@@ -11,15 +11,18 @@
   padding: 8px;
 }
 
+%ifndef MOZ_WIDGET_GTK
+% We don't let the splitter overlap the sidebar on Linux since the sidebar's
+% scrollbar is too narrow on Linux.
 .sidebar-splitter {
   -moz-appearance: none;
   border: 0 solid;
   border-inline-end-width: 1px;
   min-width: 1px;
-  width: 8px;
+  width: 4px;
   background-image: none !important;
   background-color: transparent;
-  margin-inline-start: -8px;
+  margin-inline-start: -4px;
   position: relative;
 }
 
@@ -27,8 +30,9 @@
   border-inline-end-width: 0;
   border-inline-start-width: 1px;
   margin-inline-start: 0;
-  margin-inline-end: -8px;
+  margin-inline-end: -4px;
 }
+%endif
 
 #sidebar-throbber[loading="true"] {
   list-style-image: url("chrome://global/skin/icons/loading.png");