diff --git a/components/lazdebuggers/lazdebuggerfp/fpdebugdebugger.pas b/components/lazdebuggers/lazdebuggerfp/fpdebugdebugger.pas
index 4ebee14739..ff649ec2e5 100644
--- a/components/lazdebuggers/lazdebuggerfp/fpdebugdebugger.pas
+++ b/components/lazdebuggers/lazdebuggerfp/fpdebugdebugger.pas
@@ -649,6 +649,7 @@ begin
     e := TCallStackEntry(It.DataPtr^);
     if e.Validity = ddsRequested then
     begin
+      ProcVal := nil;
       if ThreadCallStack[e.Index].ProcSymbol <> nil then
         ProcVal := ThreadCallStack[e.Index].ProcSymbol.Value;