A ruling Friday in a clash over windshield wipers may lead to more bifurcated trials in intellectual property cases—and it could spell trouble for patent plaintiffs.

It's not often that plaintiffs lawyers will fight to include fewer claims in a big class action. But that's just what happened in the consolidated securities litigation over Facebook's May 2012 initial public offering, when a pair of leading plaintiffs firms complained that smaller firms were encroaching on their territory.

Tenet claims Community Health Systems earned as much as $377 million in Medicare reimbursements by admitting patients to its hospitals who required only outpatient observation.