diff --git a/themes/tiddlywiki/vanilla/base.tid b/themes/tiddlywiki/vanilla/base.tid
index 0073486df5..bb658650a5 100644
--- a/themes/tiddlywiki/vanilla/base.tid
+++ b/themes/tiddlywiki/vanilla/base.tid
@@ -3374,7 +3374,7 @@ span.tc-translink > a:first-child {
 	margin: 0;
 }
 
-.tc-tiddler-frame .tc-edit-texteditor {
+.tc-test-case-source .tc-tiddler-frame .tc-edit-texteditor {
 	margin: 0;
 }