Hello, In the following code I analyze a textView , split it to lines , try to build a Model object from each line , and if build failed I want to color that line in red. I use setColor:range , but once called this method colors my entire view ( also previous lines ) in red. Can someone tell me what I do wrong? Thanks, David Kramf def textView(textView,doCommandBySelector:sel) puts "#{sel.to_s}" return false if sel.to_s != "insertNewline:" puts " in doCommandBySelector selector is #{sel}" @newline = true enum = @textView.string.lines(seperaotr=$/) @location = 0 enum.each_with_index do |l,i| puts "location is #{@location}" words = l.split line = Line.new(words[0],words[1]) @lines[i] = line if @lines[i] != line red = NSColor.redColor range = NSMakeRange(@location,l.length) puts "#{range.location}-#{range.length}" @textView.setTextColor(red,range) if line.rule == nil @location = @location + l.length end false end