Walmart (WMT) is suing Tesla (TSLA) for breach of contract after Tesla solar panels ignited atop seven of its stores. The suit alleges breach of contract, gross negligence, and failure to live up to industry standards. More than 240 Walmart stores have Tesla solar systems installed, and Walmart has pre-ordered at least 45 Tesla electric semi-trucks to add to its vehicle fleet, but this looks like more than just “negotiating in public.”