Fixes bug 13795 - plot corner association lost

This addresses a bug where the plot would lose the corner it was
associated with when advancing time steps in ParaView.

Change-Id: I2776680a43bb2bc0dcb40ba91e64b1a84b934455
Merge topic '13795-chart-plot-corner' into next

cd6cd55 Fixes bug 13795 - plot corner association lost