diff --git a/src/certman.hxx b/src/certman.hxx
index e4306c6..87c9f6d 100644
--- a/src/certman.hxx
+++ b/src/certman.hxx
@@ -74,7 +74,7 @@ class CertMan: public QMainWindow, protected Ui::CertMan {
                        (this,
                         win->windowTitle(),
                         win->windowTitle()
-                        .replace(" ", "_").replace(QRegExp("\.(pem|der)$"), "")
+                        .replace(" ", "_").replace(QRegExp("\\.(pem|der)$"), "")
                         +".pem",
                         tr("Certificates (*.der *.pem *.txt)")));
       if (fileName.isEmpty()) return;