diff --git a/DSView/pv/data/logicsnapshot.cpp b/DSView/pv/data/logicsnapshot.cpp
index e4e5d35d..36b0ef25 100644
--- a/DSView/pv/data/logicsnapshot.cpp
+++ b/DSView/pv/data/logicsnapshot.cpp
@@ -1236,8 +1236,8 @@ bool LogicSnapshot::pattern_search_self(int64_t start, int64_t end, int64_t &ind
     int  count = 0;  
     bool bEdgeFlag = false;
 
-    int64_t to = isNext ? end + 1 : start - 1;
-    int64_t step = isNext ? 1 : -1;
+    const int64_t to = isNext ? end + 1 : start - 1;
+    const int64_t step = isNext ? 1 : -1;
 
     for (auto it = pattern.begin(); it != pattern.end(); it++){
          char flag = *(it->second.toStdString().c_str());
@@ -1270,6 +1270,13 @@ bool LogicSnapshot::pattern_search_self(int64_t start, int64_t end, int64_t &ind
         index += step;
     }
 
+    if (index < start){
+        index = start;
+    }
+    if (index > end){
+        index = end;
+    }
+
     while (index != to)
     {
         macthed = 0;