diff --git a/DSView/pv/view/logicsignal.cpp b/DSView/pv/view/logicsignal.cpp
index 4750a115..83db2e7c 100644
--- a/DSView/pv/view/logicsignal.cpp
+++ b/DSView/pv/view/logicsignal.cpp
@@ -288,7 +288,7 @@ bool LogicSignal::measure(const QPointF &p, uint64_t &index0, uint64_t &index1,
             return false;
 
         uint64_t index = _data->samplerate() * (_view->offset() - _data->get_start_time() + p.x() * _view->scale());
-        if (index == 0)
+        if (index == 0 || index >= (snapshot->get_sample_count() - 1))
             return false;
 
         const uint64_t sig_mask = 1ULL << get_index();