make sure ax._boundingBox is defined when showticklabels is false
make sure ax._boundingBox is defined when showticklabels is false

- so that hover knows where to draw spikes

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