diff --git a/inputsource.cpp b/inputsource.cpp
index 24d182b..de1bbc5 100644
--- a/inputsource.cpp
+++ b/inputsource.cpp
@@ -71,6 +71,8 @@ void InputSource::openFile(const char *filename)
     inputFile = file;
     fileSize = size;
     mmapData = data;
+
+    invalidate();
 }
 
 std::unique_ptr<std::complex<float>[]> InputSource::getSamples(off_t start, off_t length)
diff --git a/mainwindow.cpp b/mainwindow.cpp
index 7535212..f2f8f64 100644
--- a/mainwindow.cpp
+++ b/mainwindow.cpp
@@ -31,7 +31,7 @@ MainWindow::MainWindow()
     dock->setAllowedAreas(Qt::LeftDockWidgetArea | Qt::RightDockWidgetArea);
     addDockWidget(Qt::LeftDockWidgetArea, dock);
 
-    InputSource *input = new InputSource();
+    input = new InputSource();
 
     plots = new PlotView(input);
     setCentralWidget(plots);
@@ -45,5 +45,5 @@ void MainWindow::openFile(QString fileName)
 {
     QString title="%1: %2";
     this->setWindowTitle(title.arg(QApplication::applicationName(),fileName.section('/',-1,-1)));
-    // TODO: open a file again
+    input->openFile(fileName.toUtf8().constData());
 }
diff --git a/mainwindow.h b/mainwindow.h
index 5601386..f29bd99 100644
--- a/mainwindow.h
+++ b/mainwindow.h
@@ -38,4 +38,5 @@ public slots:
 private:
     SpectrogramControls *dock;
     PlotView *plots;
+    InputSource *input;
 };
diff --git a/plotview.cpp b/plotview.cpp
index a0a0582..7822696 100644
--- a/plotview.cpp
+++ b/plotview.cpp
@@ -36,6 +36,8 @@ PlotView::PlotView(InputSource *input) : cursors(this), viewRange({0, 0})
     mainSampleSource = input;
     setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOn);
     enableCursors(false);
+
+    mainSampleSource->subscribe(this);
 }
 
 void PlotView::refreshSources()
@@ -93,13 +95,8 @@ void PlotView::enableCursors(bool enabled)
         cursors.hide();
 }
 
-void PlotView::inputSourceChanged(AbstractSampleSource *src)
+void PlotView::invalidateEvent()
 {
-    auto derived = dynamic_cast<SampleSource<std::complex<float>>*>(src);
-    if (derived == nullptr)
-        throw new std::runtime_error("SampleSource doesn't provide correct type for GRSampleBuffer");
-
-    mainSampleSource = derived;
     refreshSources();
 
     horizontalScrollBar()->setMinimum(0);
diff --git a/plotview.h b/plotview.h
index 6f6a6c0..3b204f2 100644
--- a/plotview.h
+++ b/plotview.h
@@ -27,7 +27,7 @@
 #include "plot.h"
 #include "spectrogramplot.h"
 
-class PlotView : public QAbstractScrollArea
+class PlotView : public QAbstractScrollArea, Subscriber
 {
     Q_OBJECT
 
@@ -36,7 +36,7 @@ public:
 
 public slots:
     void enableCursors(bool enable);
-    void inputSourceChanged(AbstractSampleSource *input);
+    void invalidateEvent();
     void selectionChanged(std::pair<off_t, off_t> selectionTime, std::pair<float, float> selectionFreq);
     void selectionCleared();
     void setFFTSize(int size);