fix(export): fix source combo item selection and buffer content in read mode

Replace Qt::UserRole-1 (Qt::StandardItemFlagsRole) with proper
QStandardItem::setEnabled() for disabling unavailable export sources.
The previous approach accidentally overwrote item flags, making all
source combo items unselectable.

Also fix getLatestContent() in MarkdownViewWindow2 and TextViewWindow2
to fall back to Buffer2::getContentRaw() when the editor widget is null
(read/preview mode), so the 'Current Buffer' export source is available
regardless of view mode.

Add explicit text color to QComboBox popup items across all theme QSS
files to prevent grey fallback when inside QGroupBox.

Author: tamlok

src/data/extra/themes/moonlight/interface.qss

@@ -409,12 +409,14 @@ QComboBox QAbstractItemView {
     padding: 2px;
     border: 1px solid @widgets#qcombobox#view#border;
     background-color: @widgets#qcombobox#view#bg;
+    color: @widgets#qcombobox#fg;
     selection-color: @widgets#qcombobox#view#selection#fg;
     selection-background-color: @widgets#qcombobox#view#selection#bg;
 }
 
 QComboBox QAbstractItemView::item {
     background-color: transparent;
+    color: @widgets#qcombobox#fg;
     padding: 3px;
 }
 

src/data/extra/themes/pure/interface.qss

@@ -548,12 +548,14 @@ QComboBox QAbstractItemView {
     border: 1px solid @widgets#qcombobox#view#border;
     border-radius: 4px;
     background-color: @widgets#qcombobox#view#bg;
+    color: @widgets#qcombobox#fg;
     selection-color: @widgets#qcombobox#view#selection#fg;
     selection-background-color: @widgets#qcombobox#view#selection#bg;
 }
 
 QComboBox QAbstractItemView::item {
     background-color: transparent;
+    color: @widgets#qcombobox#fg;
     padding: 4px 8px;
 }
 

src/data/extra/themes/solarized-dark/interface.qss

@@ -405,12 +405,14 @@ QComboBox QAbstractItemView {
     padding: 2px;
     border: 1px solid @widgets#qcombobox#view#border;
     background-color: @widgets#qcombobox#view#bg;
+    color: @widgets#qcombobox#fg;
     selection-color: @widgets#qcombobox#view#selection#fg;
     selection-background-color: @widgets#qcombobox#view#selection#bg;
 }
 
 QComboBox QAbstractItemView::item {
     background-color: transparent;
+    color: @widgets#qcombobox#fg;
     padding: 3px;
 }
 

src/data/extra/themes/solarized-light/interface.qss

@@ -405,12 +405,14 @@ QComboBox QAbstractItemView {
     padding: 2px;
     border: 1px solid @widgets#qcombobox#view#border;
     background-color: @widgets#qcombobox#view#bg;
+    color: @widgets#qcombobox#fg;
     selection-color: @widgets#qcombobox#view#selection#fg;
     selection-background-color: @widgets#qcombobox#view#selection#bg;
 }
 
 QComboBox QAbstractItemView::item {
     background-color: transparent;
+    color: @widgets#qcombobox#fg;
     padding: 3px;
 }
 

src/data/extra/themes/vscode-dark/interface.qss

@@ -405,12 +405,14 @@ QComboBox QAbstractItemView {
     padding: 2px;
     border: 1px solid @widgets#qcombobox#view#border;
     background-color: @widgets#qcombobox#view#bg;
+    color: @widgets#qcombobox#fg;
     selection-color: @widgets#qcombobox#view#selection#fg;
     selection-background-color: @widgets#qcombobox#view#selection#bg;
 }
 
 QComboBox QAbstractItemView::item {
     background-color: transparent;
+    color: @widgets#qcombobox#fg;
     padding: 3px;
 }
 

src/data/extra/themes/vue-dark/interface.qss

@@ -410,12 +410,14 @@ QComboBox QAbstractItemView {
     padding: 2px;
     border: 1px solid @widgets#qcombobox#view#border;
     background-color: @widgets#qcombobox#view#bg;
+    color: @widgets#qcombobox#fg;
     selection-color: @widgets#qcombobox#view#selection#fg;
     selection-background-color: @widgets#qcombobox#view#selection#bg;
 }
 
 QComboBox QAbstractItemView::item {
     background-color: transparent;
+    color: @widgets#qcombobox#fg;
     padding: 3px;
 }
 

src/data/extra/themes/vue-light/interface.qss

@@ -424,12 +424,14 @@ QComboBox QAbstractItemView {
     padding: 2px;
     border: 1px solid @widgets#qcombobox#view#border;
     background-color: @widgets#qcombobox#view#bg;
+    color: @widgets#qcombobox#fg;
     selection-color: @widgets#qcombobox#view#selection#fg;
     selection-background-color: @widgets#qcombobox#view#selection#bg;
 }
 
 QComboBox QAbstractItemView::item {
     background-color: transparent;
+    color: @widgets#qcombobox#fg;
     padding: 3px;
 }
 

src/data/extra/themes/vx-idea/interface.qss

@@ -424,12 +424,14 @@ QComboBox QAbstractItemView {
     padding: 2px;
     border: 1px solid @widgets#qcombobox#view#border;
     background-color: @widgets#qcombobox#view#bg;
+    color: @widgets#qcombobox#fg;
     selection-color: @widgets#qcombobox#view#selection#fg;
     selection-background-color: @widgets#qcombobox#view#selection#bg;
 }
 
 QComboBox QAbstractItemView::item {
     background-color: transparent;
+    color: @widgets#qcombobox#fg;
     padding: 3px;
 }
 

src/widgets/dialogs/exportdialog2.cpp

@@ -19,6 +19,7 @@
 #include <QProgressBar>
 #include <QPushButton>
 #include <QStackedLayout>
+#include <QStandardItemModel>
 #include <QTextCursor>
 #include <QUrl>
 #include <QVBoxLayout>
@@ -209,11 +210,15 @@ void ExportDialog2::setupUI() {
     auto source = static_cast<ExportSource>(i);
     m_sourceCombo->addItem(sourceText(source, m_context), i);
     const int idx = m_sourceCombo->count() - 1;
-    auto item = m_sourceCombo->model()->index(idx, 0);
-    m_sourceCombo->model()->setData(item, 1, Qt::UserRole - 1);
 
     if (!sourceAvailable(source, m_context)) {
-      m_sourceCombo->model()->setData(item, 0, Qt::UserRole - 1);
+      // Disable the item via QStandardItem flags (the proper Qt API).
+      auto *stdModel = qobject_cast<QStandardItemModel *>(m_sourceCombo->model());
+      if (stdModel) {
+        if (auto *stdItem = stdModel->item(idx)) {
+          stdItem->setEnabled(false);
+        }
+      }
       m_sourceCombo->setItemData(idx, sourceUnavailableReason(source), Qt::ToolTipRole);
     }
   }
@@ -475,10 +480,9 @@ void ExportDialog2::loadConfig() {
   restoreFields(option);
 
   const int presetIdx = m_sourceCombo->findData(static_cast<int>(m_context.presetSource));
-  if (presetIdx >= 0 &&
-      m_sourceCombo->model()
-              ->data(m_sourceCombo->model()->index(presetIdx, 0), Qt::UserRole - 1)
-              .toInt() == 1) {
+  if (presetIdx >= 0 && m_sourceCombo->model()
+                            ->flags(m_sourceCombo->model()->index(presetIdx, 0))
+                            .testFlag(Qt::ItemIsEnabled)) {
     m_sourceCombo->setCurrentIndex(presetIdx);
   }
 }
@@ -491,8 +495,8 @@ void ExportDialog2::saveConfig() {
 void ExportDialog2::restoreFields(const ExportOption &p_option) {
   int idx = m_sourceCombo->findData(static_cast<int>(p_option.m_source));
   if (idx >= 0 && m_sourceCombo->model()
-                          ->data(m_sourceCombo->model()->index(idx, 0), Qt::UserRole - 1)
-                          .toInt() == 1) {
+                      ->flags(m_sourceCombo->model()->index(idx, 0))
+                      .testFlag(Qt::ItemIsEnabled)) {
     m_sourceCombo->setCurrentIndex(idx);
   }