diff --git a/DSView/pv/view/timemarker.cpp b/DSView/pv/view/timemarker.cpp
index 0a6b049b..2fba38f2 100644
--- a/DSView/pv/view/timemarker.cpp
+++ b/DSView/pv/view/timemarker.cpp
@@ -72,8 +72,11 @@ uint64_t TimeMarker::index()
     return _index;
 }
 
-void TimeMarker::set_index(uint64_t index)
+void TimeMarker::set_index(int64_t index)
 {
+    if (index < 0){
+        index = 0;
+    }
    _index = index;
     time_changed();
 }
diff --git a/DSView/pv/view/timemarker.h b/DSView/pv/view/timemarker.h
index 84cc0bcb..7cbe8136 100644
--- a/DSView/pv/view/timemarker.h
+++ b/DSView/pv/view/timemarker.h
@@ -66,7 +66,7 @@ public:
 	/**
 	 * Sets the time of the marker.
 	 */
-    void set_index(uint64_t index);
+    void set_index(int64_t index);
 
     /**
      * Gets/Sets colour of the marker