function fetchCompletion(gc, fetchError) {
    if (!fetchError) {
        // STEP 1: Render the grid immediately (before next refresh) just to get column widths
        // (for better performance this could be done off-screen but this works fine as is)
        this.gridRenderer.paintCells.call(this, gc);
        // STEP 2: Re-render upon next refresh with proper column widths
        this.grid.repaint();
    }
}
Resets the cell properties cache in the matching `CellEvent` object from the renderer's pool. This will insure that a new cell properties object will be known to the renderer. (Normally, the cache is not reset until the pool is updated by the next call to {@link Renderer#computeCellBounds}).
@param {number|CellEvent} xOrCellEvent
@param {number} [y]
@param {DataModel} [dataModel=this.grid.behavior.dataModel]
@returns {CellEvent} The matching `CellEvent` object.