PlotStatusLabel: disconnect removed plot (#995)

GUI/View/Plotter/PlotStatusLabel.cpp

@@ -13,6 +13,7 @@
 //  ************************************************************************************************
 
 #include "GUI/View/Plotter/PlotStatusLabel.h"
+#include "Base/Util/Assert.h"
 #include "GUI/View/Base/Fontsize.h"
 #include "GUI/View/Plotter/MousyPlot.h"
 #include <QColor>
@@ -85,7 +86,10 @@ void PlotStatusLabel::setPlotLabelEnabled(MousyPlot* plot)
 
 void PlotStatusLabel::onPlotDestroyed(QObject* obj)
 {
-    auto it =
-        std::remove_if(m_plots.begin(), m_plots.end(), [obj](MousyPlot* cm) { return cm == obj; });
-    m_plots.erase(it, m_plots.end());
+    auto* old_plot = dynamic_cast<MousyPlot*>(obj);
+    ASSERT(old_plot);
+    for (auto it = m_plots.begin(); it != m_plots.end(); ++it)
+	if (*it == old_plot)
+	    m_plots.erase(it);
+    disconnect(old_plot);
 }