diff --git a/src/mainwindow.cpp b/src/mainwindow.cpp
--- a/src/mainwindow.cpp
+++ b/src/mainwindow.cpp
@@ -378,7 +378,7 @@ void MainWindow::onChannelNameChanged(un
     // This slot is triggered also when a new channel is added, in
     // this case curve list doesn't contain said channel. No worries,
     // since `onNumOfChannelsChanged` slot will update curve list.
-    if (channel < curves.size()) // check if channel exists in curve list
+    if ((int) channel < curves.size()) // check if channel exists in curve list
     {
         curves[channel]->setTitle(name);
         ui->plot->replot();