diff --git a/src/gui/MainWindow.cpp b/src/gui/MainWindow.cpp
index cc5f4887441..c516b6a7834 100644
--- a/src/gui/MainWindow.cpp
+++ b/src/gui/MainWindow.cpp
@@ -625,7 +625,7 @@ SubWindow* MainWindow::addWindowedWidget(QWidget *w, Qt::WindowFlags windowFlags
 	SubWindow *win = new SubWindow(m_workspace->viewport(), windowFlags);
 	win->setAttribute(Qt::WA_DeleteOnClose);
 	win->setWidget(w);
-	if (w->sizeHint().isValid()) {win->resize(w->sizeHint());}
+	if (w && w->sizeHint().isValid()) {win->resize(w->sizeHint());}
 	m_workspace->addSubWindow(win);
 	return win;
 }