color previous packet
I would like to colorize the first request in a sequence of two consecutive UDS requests in the filtered packets(not all packet, but the packet can pass display filter). This condition indicates that the first request did not receive a response according to the applied filter.
What do you mean by "according to the applied filter"? Whether a request received a response has nothing to do with display filters; the display filter will only control whether the request, or the response, is displayed.
A coloring rule uses a packet-matching expression, of the same sort that is used as a display filter. In either case, there would have to be a field in the packet dissection of requests indicating whether there's a response or not. Is UDS Unified Diagnostic Services?
Yes, it is Unified Diagnottic Services. There are many ECU will receve the request and only one I concern. So there is a dispay filter applied to filter all related diagnostic message. I want to know if every diagnostic request get response from ECU, so I want a color rule to find such request withou response from displayed message.