Command block command and last output display wrong aligned

When you have a long command or a long last output in a command block and then right click the command block, it shows a strange characters at the end, like it is described for MC-1237. This happens also when you press first "Pos1" and then "End". It is actually at the right position, which you can test by repeating the previous described method and holding "Shift" and copying and pasting the text then.