diff --git a/src/Editor.php b/src/Editor.php
index 04890c4..eb9cae0 100644
--- a/src/Editor.php
+++ b/src/Editor.php
@@ -528,7 +528,21 @@ class Editor {
 
 				for ($i = 0; $i < $len; $i++)
 				{
-					if ($hl[$i] === Highlight::NORMAL)
+					// Handle 'non-printable' characters
+					if (is_cntrl($c[$i]))
+					{
+						$sym = (ord($c[$i]) <= 26)
+							? chr(ord('@') + ord($c[$i]))
+							: '?';
+						$this->ab .= "\x1b[7m";
+						$this->ab .= $sym;
+						$this->ab .= "\x1b[m";
+						if ($currentColor !== -1)
+						{
+							$this->ab .= sprintf("\x1b%dm", $currentColor);
+						}
+					}
+					else if ($hl[$i] === Highlight::NORMAL)
 					{
 						if ($currentColor !== -1)
 						{