diff --git a/src/i0mapmontopoobjfilter.cpp b/src/i0mapmontopoobjfilter.cpp
index 8c31f733afd0a41eb967f572a48b966a5d92af40..14e00cacb609888bb21b0993059dd97290f890e6 100644
--- a/src/i0mapmontopoobjfilter.cpp
+++ b/src/i0mapmontopoobjfilter.cpp
@@ -41,7 +41,7 @@ bool I0MapMonObjFilter::eventFilter(QObject *watched, QEvent *event) {
                         QString ys;
                         double xsum =  bchart->baseline();
                         for(int j = 0; j < values.size(); j++) {
-                            ys += QString("λ %1: %2").arg(j+1).arg(values[j]) + "\n";
+                            ys +=  QString("λ %1: %2").arg(j+1).arg((values[j] > -1e-3 ? QString::number(values[j]) : "INVALID")) + "\n";
                             if(stacked) xsum += values[j];
                             else if(fabs(values[j]) > xsum) xsum = values[j];
                         }