Readers might be interested in this recent case in the UK Supreme Court regarding employee compensation for "outstanding benefits" from an employee's invention (Unilever made £24M selling it, he got his wage).

https://www.ipwatchdog.com/2019/10/28/uk-supreme-court-rules...

It frames the fact that employers claim ownership, and have for decades, but that UK IP law, at least, does something about that.