Fix color theme lost on AppImage

src/mainwindow.cpp

@@ -674,12 +674,11 @@ void MainWindow::init(const QString &MltPath, const QUrl &Url, const QString &cl
 void MainWindow::slotThemeChanged(const QString &theme)
 {
     disconnect(this, &MainWindow::reloadTheme, this, &MainWindow::slotReloadTheme);
+    KdenliveSettings::setColortheme(theme);
     KSharedConfigPtr config = KSharedConfig::openConfig(theme);
     setPalette(KColorScheme::createApplicationPalette(config));
     qApp->setPalette(palette());
     QPalette plt = palette();
-
-    KdenliveSettings::setColortheme(theme);
     if (m_effectStack) {
         m_effectStack->updatePalette();
         m_effectStack->transitionConfig()->updatePalette();

src/utils/thememanager.cpp

@@ -116,13 +116,30 @@ void ThemeManager::setCurrentTheme(const QString &filename)
         return;
     }
     QString name = d->themeMap.key(filename, d->defaultThemeName);
+    // In the case of AppImage, the path to the color scheme can be invalid
+    // on each start as filesystem is mounted with a random path, so check that and correct
+    if (name.isEmpty()) {
+        QMapIterator<QString, QString> i(d->themeMap);
+        while (i.hasNext()) {
+            i.next();
+            if (QFileInfo(i.value()).fileName() == QFileInfo(filename).fileName()) {
+                name = i.key();
+            }
+        }
+    }
+    bool themeFound = false;
     const QList<QAction *> list = d->themeMenuActionGroup->actions();
     for (QAction *const action : list) {
         if (action->text().remove('&') == name) {
             action->setChecked(true);
+            themeFound = true;
+            break;
             //slotChangePalette();
         }
     }
+    if (!themeFound && filename != d->defaultThemeName) {
+        setCurrentTheme(d->defaultThemeName);
+    }
 }
 
 void ThemeManager::slotChangePalette()
@@ -138,7 +155,6 @@ void ThemeManager::slotChangePalette()
     QString filename = d->themeMap.value(theme);
 
     //qCDebug(KDENLIVE_LOG) << theme << " :: " << filename;
-
     emit signalThemeChanged(filename);
 }