I filter my Logcat lines based on a single String, as depicted below:
But there I face numerous long long lines and I have much trouble recognizing the wanted values in the middle of the lines. For example, in the above picture, it would be to much convenience to see all "Aggregate" keywords highlighted.
From what I see, you use the "Filter", that will show all only lines with word matches to your filter.
If you want to search inside the filter results and get highlighted text matches, click on Cmd+s (on Mac) or Ctrl+s (on PC) and search away (for your example, type "Aggregate")