Thank you for the warning, I'll do so next time.
Lazarus is version 2.2.2 with FPC 3.2.2. System is LinuxMint 19.1 (tessa), GNOME 3.28.2 (Ubuntu), Kernel 4.15.0-188-generic (#199-Ubuntu SMP Wed Jun 15 20:42:32 UTC 2022). I hope, that will suffice.
I expected that line color is somewhere user definable.