mainwindow: pdfPreviewReceived(): Don't capture whole preview object in lambda

gui/mainwindow.cpp

@@ -129,10 +129,12 @@ void MainWindow::pdfPreviewReceived(PdfPreview preview)
 	if(preview.hasPreviewImage())
 	{
 		ClickLabel *label = new ClickLabel();
+		QString docPath = preview.documentPath;
+		auto previewPage = preview.page;
 		label->setPixmap(QPixmap::fromImage(preview.previewImage));
 		label->setToolTip(preview.documentPath);
 		ui->scrollAreaWidgetContents->layout()->addWidget(label);
-		connect(label, &ClickLabel::leftClick, [=]() {
+		connect(label, &ClickLabel::leftClick, [docPath, previewPage]() {
 			QSettings settings;
 			QString command = settings.value("pdfviewer").toString();
 			if(command != "" && command.contains("%p") && command.contains("%f"))
@@ -142,15 +144,15 @@ void MainWindow::pdfPreviewReceived(PdfPreview preview)
 				{
 					QString cmd = splitted[0];
 					QStringList args = splitted.mid(1);
-					args.replaceInStrings("%f", preview.documentPath);
-					args.replaceInStrings("%p", QString::number(preview.page));
+					args.replaceInStrings("%f", docPath);
+					args.replaceInStrings("%p", QString::number(previewPage));
 
 					QProcess::startDetached(cmd, args);
 				}
 			}
 			else
 			{
-				QDesktopServices::openUrl(QUrl::fromLocalFile(preview.documentPath));
+				QDesktopServices::openUrl(QUrl::fromLocalFile(docPath));
 			}
 		});
 	}