diff --git a/src/gui/platform/unix/qgenericunixthemes.cpp b/src/gui/platform/unix/qgenericunixthemes.cpp
index 4da0b47a4ab..3b81a6ce1a9 100644
--- a/src/gui/platform/unix/qgenericunixthemes.cpp
+++ b/src/gui/platform/unix/qgenericunixthemes.cpp
@@ -178,7 +178,6 @@ private:
         Provider provider;
         Setting setting;
         ChangeSignal(Provider p, Setting s) : provider(p), setting(s) {}
-        ChangeSignal() {}
     };
 
     QFlatMap <DBusKey, ChangeSignal> m_signalMap;
@@ -387,8 +386,9 @@ std::optional<QGenericUnixThemeDBusListener::ChangeSignal>
 {
     const DBusKey dkey(location, key);
     std::optional<QGenericUnixThemeDBusListener::ChangeSignal> ret;
-    if (m_signalMap.contains(dkey))
-        ret.emplace(m_signalMap.value(dkey));
+    const auto it = m_signalMap.find(dkey);
+    if (it != m_signalMap.cend())
+        ret.emplace(it.value());
 
     return ret;
 }