ERROR: JavaScript error: gui/session/unit_actions.js line 338
TypeError: tradingDetails.gain is null
  unitActions["setup-trade-route"].getActionInfo@gui/session/unit_actions.js:338:1
  getActionInfo@gui/session/input.js:246:8
  unitActions["setup-trade-route"].actionCheck@gui/session/unit_actions.js:350:8
  determineAction@gui/session/input.js:326:8
  updateCursorAndTooltip@gui/session/input.js:65:8
  onTick@gui/session/session.js:422:2
  __eventhandler910 (tick)@sn tick:0:1