In 2013, Red Granite, the company that ended up producing Dumb and Dumber To, actually sued Steve Stabler and Brad Krevoy in order to keep them from getting involved in the movie.
The legal battle over the sequel to Dumb and Dumber has actually been going on for quite some time.
Red Granite claimed that the producers had not been involved in the sequel in any way.
New Line was the company that distributed the original Dumb and Dumber, which made a deal to have others produce the sequel, allegedly without offering it to Stabler and Krevoy first.