keep track of hasOneHorizontalTrace in user Fx.hover calls
keep track of hasOneHorizontalTrace in user Fx.hover calls

asolagmbh/plotly.js,plotly/plotly.js,aburato/plotly.js,asolagmbh/plotly.js,aburato/plotly.js,plotly/plotly.js,etpinard/plotly.js,etpinard/plotly.js,asolagmbh/plotly.js,plotly/plotly.js,etpinard/plotly.js,plotly/plotly.js