I've been running some IDL code on Windows (IDL vers 8.7.2) and have recently been migrating to a Mac system (OS 10.15.3, IDL 8.8.0). In the IDL text editor on the Mac, on existing .pro files I used on Windows, I find that when I copy and paste multiple lines, the lines appear as one line. This makes editing programs extremely tedious. If I generate new files, there is no such issue- copy and paste of multiple lines works normally. This appears to be a "new line" character issue. In the existing files, IDL identifies the end-of-line character as a "carriage return"- looks like a little box when I turn on invisibles display. I think this implies that they are "legacy" Mac-generated files. For new files, I am able to set either Unix or Windows endings, which each include a P-looking "line feed" character, and I can copy and paste multiple lines normally. This doesn't appear to be an issue with the OS- when I open the text files in a text editor (BBEdit), I can copy and paste multiple lines normally. In fact, I can even copy and paste multiple lines from the IDL editor into the IDL command line and it treats them as multiple lines! But when copying and pasting from and to the editor, for these "legacy Mac" files, the carriage return character vanishes and all the text appears on a single line. It seems strange that this format appears to work fine on Windows but not on the Mac version of IDL. Any suggestions would be greatly appreciated!