diff --git a/content/treestyletab/treestyletab.css b/content/treestyletab/treestyletab.css
index 1786c0ba..a8d1ac80 100644
--- a/content/treestyletab/treestyletab.css
+++ b/content/treestyletab/treestyletab.css
@@ -25,7 +25,8 @@
 .tabbrowser-strip[treestyletab-tabbar-autohide="hidden"]+splitter,
 tabbrowser:not([treestyletab-tabbar-autohide="hidden"]) .treestyletab-tabbar-toggler,
 #appcontent[ahFull="true"] .tabbrowser-strip[ahHIDE="true"]+splitter /* AutoHide */,
-.tabbrowser-strip[treestyletab-tabbar-fixed="true"]+splitter {
+.tabbrowser-strip[treestyletab-tabbar-fixed="true"]+splitter,
+tabbrowser[treestyletab-tabbar-fixed="true"] .tabbrowser-strip+splitter {
 	visibility: collapse;
 }