diff --git a/src/FlatArrayTrait.php b/src/FlatArrayTrait.php
index 8108405..0dbfbd6 100644
--- a/src/FlatArrayTrait.php
+++ b/src/FlatArrayTrait.php
@@ -151,7 +151,7 @@ trait FlatArrayTrait
     {
         //normalize key names in $value, and also $name
         $value = $this->normalizeValue($value);
-        $name = strtolower($name);
+        $name = $name;
         //check for home strings
         if ($name == '' || $name === null) {
             if ($unset) {
@@ -210,7 +210,7 @@ trait FlatArrayTrait
         }
         $norm = [];
         foreach ($value as $key => $value) {
-            $nKey = preg_replace('/\./', '', strtolower($key));
+            $nKey = preg_replace('/\./', '', $key);
             if ($nKey == '') {
                 throw new \Exception("Key \"$key\" can't be used inside a FlatArray");
             }
diff --git a/tests/FlatArrayTest.php b/tests/FlatArrayTest.php
index 70d10ea..d46565b 100644
--- a/tests/FlatArrayTest.php
+++ b/tests/FlatArrayTest.php
@@ -89,19 +89,13 @@ class FlatArrayTest extends TestCase
         );
     }
 
-    public function testCaseNormalizing()
+    public function testCaseSensitivity()
     {
         $h = new FlatArray([
             'ABC'=>['ABC'=>'ABC']
         ]);
-        $this->assertEquals('ABC', $h['abc.abc']);
-        $this->assertEquals('ABC', $h['Abc.aBC']);
-        $h['Abc.aBC'] = 'abc';
-        $this->assertEquals('abc', $h['abc.abc']);
-        $this->assertEquals('abc', $h['Abc.aBC']);
-        $h['ABC'] = ['ABC'=>'ABC'];
-        $this->assertEquals('ABC', $h['abc.abc']);
-        $this->assertEquals('ABC', $h['Abc.aBC']);
+        $this->assertNull($h['abc.abc']);
+        $this->assertNull($h['Abc.aBC']);
     }
 
     public function testAccidentalSubstrings()