diff --git a/test/rendering-mss/issue_339.mss b/test/rendering-mss/issue_339.mss
new file mode 100644
index 0000000..6135740
--- /dev/null
+++ b/test/rendering-mss/issue_339.mss
@@ -0,0 +1 @@
+#poi_label[maki=''] { opacity:.5; }
\ No newline at end of file
diff --git a/test/rendering-mss/issue_339.xml b/test/rendering-mss/issue_339.xml
new file mode 100644
index 0000000..88ced86
--- /dev/null
+++ b/test/rendering-mss/issue_339.xml
@@ -0,0 +1,2 @@
+<Style name="style" filter-mode="first" opacity="0.5">
+</Style>
\ No newline at end of file