1: You can't copy/paste text to input boxes such as the title / author field. No regular text hotkeys work in fact.
>>> BitBucket: https://bitbucket.org/namida42/neolemmixplayer/issues/19/hotkeys-such-as-copy-paste-dont-work-in
2: If you change info in an input box, then do not exit out of the input box and save the level, the info in that box will not be saved.
>>> BitBucket: https://bitbucket.org/namida42/neolemmixplayer/issues/20/changes-in-input-boxes-arent-applied-if
1. You can copy / paste by right clicking and choosing "Copy" / "Paste". I'm aware that you can't use the hotkeys, but have no idea why this happens.
2. Fixed for the next update.