From this article just posted on the NY Times website:

Democrats, who had already given into Republicans’ long-held dreams of large tax cuts for small businesses and for some of the entertainment industry and a proposed $10,000 tax break for first-time home buyers, balked at Mr. Maldonado’s request that the legislature tuck a bill into the package that would allow voters to cross party lines in primary elections.
Mr. Maldonado, who is also seeking a constitutional amendment to prevent lawmakers from getting paid if budgets are late, defended his request that the open primary bill be included in the budget package.
“There needs to be good government reforms in this budget, and no member should be getting pet projects,” he said. “I think with an open primary, we would have good government that would do the people’s work.”

I presume the request would be for a legislative ballot measure that would put the issue before the people, as Prop. 60 enshrined the parties’ right to a closed primary in the California Constitution.
UPDATE: More on the open primary demand here.