diff --git a/lib/reline/line_editor.rb b/lib/reline/line_editor.rb
index 9ea0f0731b..9df04f14f4 100644
--- a/lib/reline/line_editor.rb
+++ b/lib/reline/line_editor.rb
@@ -651,7 +651,9 @@ class Reline::LineEditor
           bg_color = '46'
         end
       end
-      @output.write "\e[#{bg_color}m%-#{dialog.width}s\e[49m" % Reline::Unicode.take_range(item, 0, dialog.width)
+      str = Reline::Unicode.take_range(item, 0, dialog.width)
+      str += ' ' * (dialog.width - calculate_width(str, true))
+      @output.write "\e[#{bg_color}m#{str}\e[49m"
       Reline::IOGate.move_cursor_column(dialog.column)
       move_cursor_down(1) if i < (dialog.contents.size - 1)
     end