diff --git a/client/src/cmddata.c b/client/src/cmddata.c
index 47599c5de..f9bef7083 100644
--- a/client/src/cmddata.c
+++ b/client/src/cmddata.c
@@ -30,7 +30,7 @@
 
 uint8_t DemodBuffer[MAX_DEMOD_BUF_LEN];
 size_t DemodBufferLen = 0;
-size_t g_DemodStartIdx = 0;
+int32_t g_DemodStartIdx = 0;
 int g_DemodClock = 0;
 
 static int CmdHelp(const char *Cmd);
@@ -1789,6 +1789,7 @@ int CmdLtrim(const char *Cmd) {
         GraphBuffer[i - ds] = GraphBuffer[i];
 
     GraphTraceLen -= ds;
+    g_DemodStartIdx -= ds;
     RepaintGraphWindow();
     return PM3_SUCCESS;
 }
diff --git a/client/src/cmddata.h b/client/src/cmddata.h
index 86a60a9bb..b009aaaf8 100644
--- a/client/src/cmddata.h
+++ b/client/src/cmddata.h
@@ -86,7 +86,7 @@ extern uint8_t DemodBuffer[MAX_DEMOD_BUF_LEN];
 extern size_t DemodBufferLen;
 
 extern int g_DemodClock;
-extern size_t g_DemodStartIdx;
+extern int32_t g_DemodStartIdx;
 
 #ifdef __cplusplus
 }
diff --git a/client/src/proxguiqt.cpp b/client/src/proxguiqt.cpp
index 8c0651b10..6436b5b85 100644
--- a/client/src/proxguiqt.cpp
+++ b/client/src/proxguiqt.cpp
@@ -703,6 +703,16 @@ void Plot::Trim(void) {
     if ((CursorAPos == 0) || (CursorBPos == 0)) { // if we don't have both cursors set
         lref = GraphStart;
         rref = GraphStop;
+        if (CursorAPos >= lref) {
+            CursorAPos -= lref;
+        } else {
+            CursorAPos = 0;
+        }
+        if (CursorBPos >= lref) {
+            CursorBPos -= lref;
+        } else {
+            CursorBPos = 0;
+        }
     } else {
         lref = CursorAPos < CursorBPos ? CursorAPos : CursorBPos;
         rref = CursorAPos < CursorBPos ? CursorBPos : CursorAPos;
@@ -715,6 +725,7 @@ void Plot::Trim(void) {
         CursorAPos -= lref;
         CursorBPos -= lref;
     }
+    g_DemodStartIdx -= lref;
     for (uint32_t i = lref; i < rref; ++i)
         GraphBuffer[i - lref] = GraphBuffer[i];
     GraphTraceLen = rref - lref;