ui: picking folders and files only works on Mac OS

src/lib_gui/qt/element/QtDirectoryListBox.cpp

@@ -4,6 +4,7 @@
 #include <QFileDialog>
 #include <QMimeData>
 #include <QScrollBar>
+#include <QSysInfo>
 #include <QTreeView>
 
 #include "utility/ResourcePaths.h"
@@ -57,6 +58,11 @@ void QtListItemWidget::handleButtonPress()
 {
 	QFileDialog dialog(this);
 
+	if (QSysInfo::macVersion() == QSysInfo::MV_None)
+	{
+		dialog.setFileMode(QFileDialog::Directory);
+	}
+
 	if (m_data->text().size())
 	{
 		dialog.setDirectory(m_data->text());