Some places yes. It's a little different, at least it has been in all my contracts. The company you work for has the rights to buy the software from you, at a reasonable price. If they don't want it, you free to do whatever. They can't just take it.
I had colleagues would worked on a project in their space time, their price was reasonable wanting only compensation for the hours spend working on. The company didn't want it, but they also could not sell it, because if was so heavily tied into our systems and work flows that they couldn't reasonably sell it anywhere else.
One of those developers then started working on another project, one that was so fare away from what we did that there was no way the company would want it and turned that project into a very successful business.
In reality what happens is that people will work on something, quit, and the spend a few months on polishing and then release their project or sell it. Very few companies will want to spend time going after a former employee building some side business far removed from their core business.
I had colleagues would worked on a project in their space time, their price was reasonable wanting only compensation for the hours spend working on. The company didn't want it, but they also could not sell it, because if was so heavily tied into our systems and work flows that they couldn't reasonably sell it anywhere else.
One of those developers then started working on another project, one that was so fare away from what we did that there was no way the company would want it and turned that project into a very successful business.
In reality what happens is that people will work on something, quit, and the spend a few months on polishing and then release their project or sell it. Very few companies will want to spend time going after a former employee building some side business far removed from their core business.