diff --git a/src/source_base.cpp b/src/source_base.cpp
index 4d81863..d6dc5ad 100644
--- a/src/source_base.cpp
+++ b/src/source_base.cpp
@@ -310,6 +310,8 @@ void Source::CommonView::copy_lines() {
 bool Source::CommonView::copy_with_first_line_indentation() {
   Gtk::TextIter start, end;
   get_buffer()->get_selection_bounds(start, end);
+  if(start.get_line() == end.get_line())
+    return false;
 
   auto line_start = start;
   while(!line_start.starts_line() && line_start.backward_char() && (*line_start == ' ' || *line_start == '\t')) {