GH-2859 improve UI for twitch pack import with drag&drop

application/widgets/DropLabel.cpp

@@ -0,0 +1,41 @@
+#include "DropLabel.h"
+
+#include <QMimeData>
+#include <QDropEvent>
+
+DropLabel::DropLabel(QWidget *parent) : QLabel(parent)
+{
+    setAcceptDrops(true);
+}
+
+void DropLabel::dragEnterEvent(QDragEnterEvent *event)
+{
+    event->acceptProposedAction();
+}
+
+void DropLabel::dragMoveEvent(QDragMoveEvent *event)
+{
+    event->acceptProposedAction();
+}
+
+void DropLabel::dragLeaveEvent(QDragLeaveEvent *event)
+{
+    event->accept();
+}
+
+void DropLabel::dropEvent(QDropEvent *event)
+{
+    const QMimeData *mimeData = event->mimeData();
+
+    if (!mimeData)
+    {
+        return;
+    }
+
+    if (mimeData->hasUrls()) {
+        auto urls = mimeData->urls();
+        emit droppedURLs(urls);
+    }
+
+    event->acceptProposedAction();
+}