diff --git a/gtkblueprinttool/ast.py b/gtkblueprinttool/ast.py
index d2251f7..67ec208 100644
--- a/gtkblueprinttool/ast.py
+++ b/gtkblueprinttool/ast.py
@@ -43,7 +43,8 @@ class UI(AstNode):
 
         for i in self.children[Import]:
             try:
-                gir_ctx.add_namespace(i.gir_namespace)
+                if i.gir_namespace is not None:
+                    gir_ctx.add_namespace(i.gir_namespace)
             except CompileError as e:
                 self._gir_errors.append(e)
 
diff --git a/tests/samples/strings.blp b/tests/samples/strings.blp
new file mode 100644
index 0000000..6ea0f7d
--- /dev/null
+++ b/tests/samples/strings.blp
@@ -0,0 +1,5 @@
+using Gtk 4.0;
+
+Label {
+  label: "Test 1 2 3\n & 4 \"5\" 6";
+}
diff --git a/tests/samples/strings.ui b/tests/samples/strings.ui
new file mode 100644
index 0000000..6350ddf
--- /dev/null
+++ b/tests/samples/strings.ui
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<interface>
+  <requires lib="gtk" version="4.0"/>
+  <object class="GtkLabel">
+    <property name="label">Test 1 2 3
+ &amp; 4 "5" 6</property>
+  </object>
+</interface>
diff --git a/tests/test_samples.py b/tests/test_samples.py
index bdaa92d..08d376e 100644
--- a/tests/test_samples.py
+++ b/tests/test_samples.py
@@ -62,6 +62,7 @@ class TestSamples(unittest.TestCase):
         self.assert_sample("menu")
         self.assert_sample("property")
         self.assert_sample("signal")
+        self.assert_sample("strings")
         self.assert_sample("style")
         self.assert_sample("template")
         self.assert_sample("using")