diff --git a/arduino-ide-extension/src/browser/style/main.css b/arduino-ide-extension/src/browser/style/main.css
index 0cde7e13..14d5f040 100644
--- a/arduino-ide-extension/src/browser/style/main.css
+++ b/arduino-ide-extension/src/browser/style/main.css
@@ -132,6 +132,10 @@
     box-sizing: border-box;
 }
 
+.theia-output .monaco-editor .margin {
+    border-right: none;
+}
+
 .noWrapInfo {
     white-space: nowrap;
     overflow: hidden;