diff --git a/src/gui/uithememanager.cpp b/src/gui/uithememanager.cpp
index 43d076e6f..15cf93fe4 100644
--- a/src/gui/uithememanager.cpp
+++ b/src/gui/uithememanager.cpp
@@ -31,7 +31,6 @@
 
 #include <QApplication>
 #include <QFile>
-#include <QIcon>
 #include <QJsonDocument>
 #include <QJsonObject>
 #include <QPalette>
@@ -127,14 +126,15 @@ QIcon UIThemeManager::getIcon(const QString &iconId, const QString &fallback) co
         return icon;
     }
 #endif
-    // cache to avoid rescaling svg icons
-    static QHash<QString, QIcon> iconCache;
-    const auto iter = iconCache.find(iconId);
-    if (iter != iconCache.end())
+
+    // Cache to avoid rescaling svg icons
+    // And don't cache system icons because users might change them at run time
+    const auto iter = m_iconCache.find(iconId);
+    if (iter != m_iconCache.end())
         return *iter;
 
     const QIcon icon {getIconPathFromResources(iconId, fallback)};
-    iconCache[iconId] = icon;
+    m_iconCache[iconId] = icon;
     return icon;
 }
 
@@ -153,7 +153,7 @@ QString UIThemeManager::getIconPath(const QString &iconId) const
 {
 #if (defined(Q_OS_UNIX) && !defined(Q_OS_MACOS))
     if (m_useSystemTheme) {
-        QString path = Utils::Fs::tempPath() + iconId + ".png";
+        QString path = Utils::Fs::tempPath() + iconId + QLatin1String(".png");
         if (!QFile::exists(path)) {
             const QIcon icon = QIcon::fromTheme(iconId);
             if (!icon.isNull())
diff --git a/src/gui/uithememanager.h b/src/gui/uithememanager.h
index 95166d918..3eb3b0a21 100644
--- a/src/gui/uithememanager.h
+++ b/src/gui/uithememanager.h
@@ -31,6 +31,7 @@
 
 #include <QColor>
 #include <QHash>
+#include <QIcon>
 #include <QObject>
 #include <QString>
 
@@ -60,6 +61,7 @@ private:
 
     static UIThemeManager *m_instance;
     QHash<QString, QColor> m_colors;
+    mutable QHash<QString, QIcon> m_iconCache;
     const bool m_useCustomTheme;
 #if (defined(Q_OS_UNIX) && !defined(Q_OS_MACOS))
     bool m_useSystemTheme;