diff --git a/TODO b/TODO
index 2a6802f..8a0ae23 100644
--- a/TODO
+++ b/TODO
@@ -25,5 +25,6 @@ type:file
 endswith:
 startswith:
 mtime:
-
+tag:
+page:
 SearchWorker::setFilters()
diff --git a/gui/mainwindow.cpp b/gui/mainwindow.cpp
index 5b823fd..6b8ee81 100644
--- a/gui/mainwindow.cpp
+++ b/gui/mainwindow.cpp
@@ -119,6 +119,9 @@ void MainWindow::makePdfPreview()
 {
 	if(!pdfWorkerThread.isRunning())
 		pdfWorkerThread.start();
+
+	pdfWorker->cancelAndWait();
+	QCoreApplication::processEvents(); // Process not processed images
 	qDeleteAll(ui->scrollAreaWidgetContents->children());
 
 	ui->scrollAreaWidgetContents->setLayout(new QHBoxLayout());
diff --git a/gui/pdfworker.cpp b/gui/pdfworker.cpp
index da8ccd4..6fc5d26 100644
--- a/gui/pdfworker.cpp
+++ b/gui/pdfworker.cpp
@@ -14,15 +14,25 @@ Poppler::Document *PdfWorker::document(QString path)
 		return this->documentcache.value(path);
 
 	Poppler::Document *result = Poppler::Document::load(path);
+	if(result == nullptr)
+	{
+		return nullptr;
+	}
 	result->setRenderHint(Poppler::Document::TextAntialiasing);
 	this->documentcache.insert(path, result);
 	return result;
 }
 void PdfWorker::generatePreviews(QVector<SearchResult> paths, double scalefactor)
 {
+	this->cancelCurrent = false;
+	this->generating = true;
 	for(SearchResult &sr : paths)
 	{
 		Poppler::Document *doc = document(sr.path);
+		if(doc == nullptr)
+		{
+			continue;
+		}
 		qDebug() << sr.path;
 		if(doc->isLocked())
 		{
@@ -39,6 +49,27 @@ void PdfWorker::generatePreviews(QVector<SearchResult> paths, double scalefactor
 		preview.previewImage = image;
 		preview.documentPath = sr.path;
 		emit previewReady(preview);
+		if(this->cancelCurrent.load())
+		{
+
+			break;
+		}
 	}
+	isFreeMutex.lock();
+	isFree.wakeOne();
+	isFreeMutex.unlock();
+	generating = false;
 	emit previewsFinished();
 }
+
+void PdfWorker::cancelAndWait()
+{
+	if(this->generating.load())
+	{
+		this->cancelCurrent = true;
+
+		isFreeMutex.lock();
+		isFree.wait(&isFreeMutex);
+		isFreeMutex.unlock();
+	}
+}
diff --git a/gui/pdfworker.h b/gui/pdfworker.h
index 7b243b2..33f4672 100644
--- a/gui/pdfworker.h
+++ b/gui/pdfworker.h
@@ -3,6 +3,9 @@
 #include <QObject>
 #include <QImage>
 #include <QHash>
+#include <QThread>
+#include <QMutex>
+#include <QWaitCondition>
 #include <poppler-qt5.h>
 #include "pdfpreview.h"
 #include "searchresult.h"
@@ -13,9 +16,14 @@ class PdfWorker : public QObject
   private:
 	QHash<QString, Poppler::Document *> documentcache;
 	Poppler::Document *document(QString path);
+	std::atomic<bool> cancelCurrent{false};
+	std::atomic<bool> generating{false};
+	QMutex isFreeMutex;
+	QWaitCondition isFree;
 
   public:
 	PdfWorker();
+	void cancelAndWait();
   public slots:
 	void generatePreviews(QVector<SearchResult> paths, double scalefactor);
   signals:
diff --git a/gui/searchworker.cpp b/gui/searchworker.cpp
index db44057..bace4aa 100644
--- a/gui/searchworker.cpp
+++ b/gui/searchworker.cpp
@@ -21,6 +21,12 @@ SearchWorker::SearchWorker(const QString &dbpath)
 						  "content_fts.content MATCH ? ORDER By file.mtime DESC, content.page ASC");
 }
 
+QString normalize(QString str)
+{
+	str = str.replace(" ", " AND ");
+	str = str.replace("|", " OR ");
+	return str;
+}
 void SearchWorker::searchForFile(const QString &query)
 {
 	QVector<SearchResult> results;