dolphinnavigatorswidgetaction: show focus indicator in split mode

This commit uses KUrlNavigator focus indicator to show sufficiently which panel (left or right) is currently active in split mode.

This MR is based on KIO changes in https://invent.kde.org/frameworks/kio/-/merge_requests/2054

See discussion in MR: !1076 (comment 1334290), see https://invent.kde.org/frameworks/kio/-/merge_requests/2058

@teams/vdg

![Screenshot_20251117_232634.png](/uploads/2999f35fdc1c6dd359621c60d23460f2/Screenshot_20251117_232634.png){width=849 height=313}

![Screenshot_20251117_232704.png](/uploads/bd7b75f9159ab533b8e446781233e027/Screenshot_20251117_232704.png){width=849 height=313}

![Screenshot_20251117_232740.png](/uploads/e07153c1e9ae162ebc0ff3f09df1ac34/Screenshot_20251117_232740.png){width=849 height=313}

![Screenshot_20251117_232752.png](/uploads/ececd4c70c0e1f67145e2486d1cf21f2/Screenshot_20251117_232752.png){width=849 height=313}

@teams/vdg

BUG: 150718

BUG: 428440

2 files changed, 8 insertions, 4 deletions

diff --git a/src/dolphinnavigatorswidgetaction.cpp b/src/dolphinnavigatorswidgetaction.cpp
index ef99d1cb7..93d6859b1 100644
--- a/src/dolphinnavigatorswidgetaction.cpp
+++ b/src/dolphinnavigatorswidgetaction.cpp
@@ -22,8 +22,6 @@
 #include <QStyle>
 #include <QToolBar>
 
-#include <limits>
-
 DolphinNavigatorsWidgetAction::DolphinNavigatorsWidgetAction(QWidget *parent)
     : QWidgetAction{parent}
     , m_splitter{new QSplitter(Qt::Horizontal)}
@@ -149,6 +147,12 @@ void DolphinNavigatorsWidgetAction::setSecondaryNavigatorVisible(bool visible)
         // Fix an unlikely event of wrong trash button visibility.
         emptyTrashButton(Secondary)->setVisible(false);
     }
+#if KIO_VERSION >= QT_VERSION_CHECK(6, 21, 0)
+    primaryUrlNavigator()->setHighlightFocusIndicator(visible);
+    if (secondaryUrlNavigator()) {
+        secondaryUrlNavigator()->setHighlightFocusIndicator(visible);
+    }
+#endif
     updateText();
 }
 
@@ -329,7 +333,7 @@ DolphinNavigatorsWidgetAction::ViewGeometriesHelper::ViewGeometriesHelper(QWidge
 bool DolphinNavigatorsWidgetAction::ViewGeometriesHelper::eventFilter(QObject *watched, QEvent *event)
 {
     if (event->type() == QEvent::Resize) {
-        if (qobject_cast<QWidget*>(m_navigatorsWidgetAction->parent())->window()->width() != m_navigatorsWidgetAction->m_previousWindowWidth) {
+        if (qobject_cast<QWidget *>(m_navigatorsWidgetAction->parent())->window()->width() != m_navigatorsWidgetAction->m_previousWindowWidth) {
             // The window is being resized which means not all widgets have gotten their new sizes yet.
             // Let's wait a bit so the sizes of the navigatorsWidget and the viewContainers have all
             // had a chance to be updated.
diff --git a/src/dolphintabpage.cpp b/src/dolphintabpage.cpp
index f6ccff22e..1ceda7d9f 100644
--- a/src/dolphintabpage.cpp
+++ b/src/dolphintabpage.cpp
@@ -25,11 +25,11 @@ void resetSplitterSizes(QSplitter *splitter)
 
 DolphinTabPage::DolphinTabPage(const QUrl &primaryUrl, const QUrl &secondaryUrl, QWidget *parent)
     : QWidget(parent)
-    , m_splitterLastPosition(0)
     , m_expandingContainer{nullptr}
     , m_primaryViewActive(true)
     , m_splitViewEnabled(false)
     , m_active(true)
+    , m_splitterLastPosition(0)
 {
     QGridLayout *layout = new QGridLayout(this);
     layout->setSpacing(0);