valuesToHighlight method
Returns true if there are values to highlight, false if there are no values to highlight. Checks if the highlight array is null, has a length of zero or if the first object is null.
@return
Implementation
bool valuesToHighlight() {
// TODO: Removed (_indicesToHighlight![0] == null), correct?
var res = _indicesToHighlight == null || _indicesToHighlight!.isEmpty
? false
: true;
return res;
}