diff --git a/tools/lammps-gui/codeeditor.cpp b/tools/lammps-gui/codeeditor.cpp
index 6acba416f2..b438e51319 100644
--- a/tools/lammps-gui/codeeditor.cpp
+++ b/tools/lammps-gui/codeeditor.cpp
@@ -28,7 +28,7 @@
 #include <QTextBlock>
 #include <QUrl>
 
-CodeEditor::CodeEditor(QWidget *parent) : QPlainTextEdit(parent), highlight(-1)
+CodeEditor::CodeEditor(QWidget *parent) : QPlainTextEdit(parent), highlight(NO_HIGHLIGHT)
 {
     help_action = new QShortcut(QKeySequence::fromString("Ctrl+?"), parent);
     connect(help_action, &QShortcut::activated, this, &CodeEditor::get_help);
@@ -94,11 +94,9 @@ void CodeEditor::setFont(const QFont &newfont)
     document()->setDefaultFont(newfont);
 }
 
-void CodeEditor::setHighlight(int block)
+void CodeEditor::setCursor(int block)
 {
-    highlight   = block;
-
-    // also move cursor to current position
+    // move cursor to given position
     auto cursor = textCursor();
     int moves   = block - cursor.blockNumber();
     if (moves < 0)
@@ -106,6 +104,17 @@ void CodeEditor::setHighlight(int block)
     else
         cursor.movePosition(QTextCursor::Down, QTextCursor::MoveAnchor, moves);
     setTextCursor(cursor);
+}
+
+void CodeEditor::setHighlight(int block, bool error)
+{
+    if (error)
+        highlight = -block;
+    else
+        highlight = block;
+
+    // also reset the cursor
+    setCursor(block);
 
     // update graphics
     repaint();
@@ -173,12 +182,17 @@ void CodeEditor::lineNumberAreaPaintEvent(QPaintEvent *event)
     while (block.isValid() && top <= event->rect().bottom()) {
         if (block.isVisible() && bottom >= event->rect().top()) {
             QString number = QString::number(blockNumber + 1) + " ";
-            if ((highlight < 0) || (blockNumber != highlight)) {
+            if ((highlight == NO_HIGHLIGHT) || (blockNumber != std::abs(highlight))) {
                 painter.setPen(Qt::black);
             } else {
                 number = QString(">") + QString::number(blockNumber + 1) + "<";
-                painter.fillRect(0, top, lineNumberArea->width(), fontMetrics().height(),
-                                 Qt::darkRed);
+                if (highlight < 0)
+                    painter.fillRect(0, top, lineNumberArea->width(), fontMetrics().height(),
+                                     Qt::darkRed);
+                else
+                    painter.fillRect(0, top, lineNumberArea->width(), fontMetrics().height(),
+                                     Qt::darkGreen);
+
                 painter.setPen(Qt::white);
             }
             painter.drawText(0, top, lineNumberArea->width(), fontMetrics().height(),
diff --git a/tools/lammps-gui/codeeditor.h b/tools/lammps-gui/codeeditor.h
index 0f2dc51c65..0b372f1bfb 100644
--- a/tools/lammps-gui/codeeditor.h
+++ b/tools/lammps-gui/codeeditor.h
@@ -29,7 +29,10 @@ public:
     void lineNumberAreaPaintEvent(QPaintEvent *event);
     int lineNumberAreaWidth();
     void setFont(const QFont &newfont);
-    void setHighlight(int block);
+    void setCursor(int block);
+    void setHighlight(int block, bool error);
+
+    static constexpr int NO_HIGHLIGHT = 1 << 30;
 
 protected:
     void resizeEvent(QResizeEvent *event) override;
diff --git a/tools/lammps-gui/lammpsgui.cpp b/tools/lammps-gui/lammpsgui.cpp
index f0a9828775..548ce4906d 100644
--- a/tools/lammps-gui/lammpsgui.cpp
+++ b/tools/lammps-gui/lammpsgui.cpp
@@ -504,6 +504,7 @@ void LammpsGui::open_file(const QString &fileName)
                 break;
         }
     }
+    ui->textEdit->setHighlight(CodeEditor::NO_HIGHLIGHT, false);
 
     QFileInfo path(fileName);
     current_file = path.fileName();
@@ -527,6 +528,7 @@ void LammpsGui::open_file(const QString &fileName)
     ui->textEdit->document()->setModified(false);
     file.close();
     dirstatus->setText(QString(" Directory: ") + current_dir);
+    status->setText("Ready.");
 
     update_variables();
 }
@@ -665,7 +667,7 @@ void LammpsGui::logupdate()
         void *ptr = lammps.last_thermo("line", 0);
         if (ptr) {
             nline = *((int *)ptr);
-            ui->textEdit->setHighlight(nline);
+            ui->textEdit->setHighlight(nline, false);
         }
     }
 
@@ -755,7 +757,7 @@ void LammpsGui::run_done()
     delete logupdater;
     logupdater = nullptr;
     progress->setValue(1000);
-    ui->textEdit->setHighlight(-1);
+    ui->textEdit->setHighlight(CodeEditor::NO_HIGHLIGHT, false);
 
     capturer->EndCapture();
     auto log = capturer->GetCapture();
@@ -800,13 +802,19 @@ void LammpsGui::run_done()
         success = false;
     }
 
+    int nline = CodeEditor::NO_HIGHLIGHT;
+    void *ptr = lammps.last_thermo("line", 0);
+    if (ptr) nline = *((int *)ptr);
+
     if (success) {
         status->setText("Ready.");
     } else {
         status->setText("Failed.");
+        ui->textEdit->setHighlight(nline, true);
         QMessageBox::critical(this, "LAMMPS-GUI Error",
                               QString("Error running LAMMPS:\n\n") + errorbuf);
     }
+    ui->textEdit->setCursor(nline);
     progress->hide();
     dirstatus->show();
 }
diff --git a/tools/lammps-gui/lammpsrunner.h b/tools/lammps-gui/lammpsrunner.h
index a864282924..44a56d00a7 100644
--- a/tools/lammps-gui/lammpsrunner.h
+++ b/tools/lammps-gui/lammpsrunner.h
@@ -42,7 +42,7 @@ public:
     {
         lammps = _lammps;
         input  = _input;
-        file = _file;
+        file   = _file;
         lammps->command("clear");
     }
 
diff --git a/tools/lammps-gui/preferences.cpp b/tools/lammps-gui/preferences.cpp
index 7ce80261a9..bdb7d39dbf 100644
--- a/tools/lammps-gui/preferences.cpp
+++ b/tools/lammps-gui/preferences.cpp
@@ -397,7 +397,7 @@ SnapshotTab::SnapshotTab(QSettings *_settings, QWidget *parent) :
     auto *ssao  = new QLabel("HQ Image mode:");
     auto *bbox  = new QLabel("Show Box:");
     auto *axes  = new QLabel("Show Axes:");
-    auto *vdw  = new QLabel("VDW Style:");
+    auto *vdw   = new QLabel("VDW Style:");
     auto *cback = new QLabel("Background Color:");
     auto *cbox  = new QLabel("Box Color:");
     settings->beginGroup("snapshot");
diff --git a/tools/lammps-gui/run-file.png b/tools/lammps-gui/run-file.png
new file mode 100644
index 0000000000..abe4f716fb
Binary files /dev/null and b/tools/lammps-gui/run-file.png differ