Helicorder in a Bootstrap card fails to display the UTC and/or UTC and Local y-axis labels #67
Description
If you place a helicorder display in a Bootstrap card, the UTC and/or UTC and Local y-axis labels will not show up due to the z-index being set to -1 at https://github.com/crotwell/seisplotjs/blob/e51d5ee15d2d187cce73ae8bb5e695512b820254/src/helicorder.ts#L322.