edit-miscellaneous-multi-select all matches works bad on big file (~30mb)

[CyanTailwinds]

i have a log file(~30mb) and i want to find some rows contains my keyword, then i want to copy them to a new file for further work. i successfully find all lines with regex (they become highlightend correctly) ,but when i click edit-miscellaneous-multi-select all matches ,after program suspend for a while , target lines cannot be selected.

i build a test file with about 20 lines for test . multi-select all matches works correctly, i can copy multi lines to a new file