diff --git a/src/plugins/texteditor/refactoroverlay.cpp b/src/plugins/texteditor/refactoroverlay.cpp
index e1f6ff2c7cd..a0c928858ca 100644
--- a/src/plugins/texteditor/refactoroverlay.cpp
+++ b/src/plugins/texteditor/refactoroverlay.cpp
@@ -25,14 +25,17 @@ RefactorOverlay::RefactorOverlay(TextEditor::TextEditorWidget *editor) :
 void RefactorOverlay::paint(QPainter *painter, const QRect &clip)
 {
     const auto firstBlock = m_editor->blockForVerticalOffset(clip.top());
+    const int firstBlockNumber = firstBlock.isValid() ? firstBlock.blockNumber() : 0;
     const auto lastBlock = m_editor->blockForVerticalOffset(clip.bottom());
+    const int lastBlockNumber = lastBlock.isValid() ? lastBlock.blockNumber()
+                                                    : m_editor->blockCount() - 1;
 
     m_maxWidth = 0;
     for (const RefactorMarker &marker : std::as_const(m_markers)) {
         const int markerBlockNumber = marker.cursor.block().blockNumber();
-        if (markerBlockNumber < firstBlock.blockNumber())
+        if (markerBlockNumber < firstBlockNumber)
             continue;
-        if (markerBlockNumber > lastBlock.blockNumber())
+        if (markerBlockNumber > lastBlockNumber)
             continue;
         paintMarker(marker, painter, clip);
     }
diff --git a/src/plugins/texteditor/texteditoroverlay.cpp b/src/plugins/texteditor/texteditoroverlay.cpp
index 4dfed80728b..ca15ff256bf 100644
--- a/src/plugins/texteditor/texteditoroverlay.cpp
+++ b/src/plugins/texteditor/texteditoroverlay.cpp
@@ -334,11 +334,14 @@ void TextEditorOverlay::paint(QPainter *painter, const QRect &clip)
     Q_UNUSED(clip)
 
     const auto firstBlock = m_editor->blockForVerticalOffset(clip.top());
+    const int firstBlockNumber = firstBlock.isValid() ? firstBlock.blockNumber() : 0;
     const auto lastBlock = m_editor->blockForVerticalOffset(clip.bottom());
+    const int lastBlockNumber = lastBlock.isValid() ? lastBlock.blockNumber()
+                                                    : m_editor->blockCount() - 1;
 
     auto overlapsClip = [&](const OverlaySelection &selection) {
-        return selection.m_cursor_end.blockNumber() >= firstBlock.blockNumber()
-               && selection.m_cursor_begin.blockNumber() <= lastBlock.blockNumber();
+        return selection.m_cursor_end.blockNumber() >= firstBlockNumber
+               && selection.m_cursor_begin.blockNumber() <= lastBlockNumber;
     };
 
     for (int i = m_selections.size() - 1; i >= 0; --i) {