diff --git a/src/ProtectedGlobal.php b/src/ProtectedGlobal.php
index d2fecf7..c7dfe41 100644
--- a/src/ProtectedGlobal.php
+++ b/src/ProtectedGlobal.php
@@ -6,7 +6,7 @@
 class ProtectedGlobal implements ArrayAccess {
 	const WARNING_MESSAGE = "Global variables are protected - see https://php.gt/globals";
 
-	public $whiteListData = [];
+	protected $whiteListData;
 
 	public function __construct(array $whiteListData = []) {
 		$this->whiteListData = $whiteListData;
@@ -19,7 +19,7 @@ public function __toString():string {
 	public function __debugInfo():array {
 		return array_merge([
 			"WARNING" => (string)$this,
-		], $this->whiteListData);
+		], $this->whiteListData ?? []);
 	}
 
 	public function offsetExists($offset):bool {
@@ -41,6 +41,7 @@ public function offsetGet($offset) {
 	public function offsetSet($offset, $value):void {
 		if(array_key_exists($offset, $this->whiteListData)) {
 			$this->whiteListData[$offset] = $value;
+			return;
 		}
 
 		$this->throwException();
@@ -49,6 +50,7 @@ public function offsetSet($offset, $value):void {
 	public function offsetUnset($offset):void {
 		if(array_key_exists($offset, $this->whiteListData)) {
 			unset($this->whiteListData);
+			return;
 		}
 
 		$this->throwException();
diff --git a/test/unit/ProtectedGlobalTest.php b/test/unit/ProtectedGlobalTest.php
index 9ec95a7..2c490e2 100644
--- a/test/unit/ProtectedGlobalTest.php
+++ b/test/unit/ProtectedGlobalTest.php
@@ -54,4 +54,23 @@ public function testOffsetSetThrowsException() {
 		self::expectException(ProtectedGlobalException::class);
 		$sut["something"] = "broken";
 	}
+
+	public function testOffsetSet() {
+		$whiteList = [
+			"name" => "test",
+		];
+		$sut = new ProtectedGlobal($whiteList);
+		$sut["name"] = "changed";
+
+		self::assertEquals("changed", $sut["name"]);
+	}
+
+	public function testOffsetUnsetThrowsException() {
+		$whiteList = [
+			"name" => "test",
+		];
+		$sut = new ProtectedGlobal($whiteList);
+		self::expectException(ProtectedGlobalException::class);
+		unset($sut["something"]);
+	}
 }
\ No newline at end of file