Changed from IMCP ping sweep to arp first hybrid scanning and added TCP and UDP port databases to show port names/functions when scanning. I couldn’t stand the way the UI blocked when it was scanning. I thought it was caused by the scan being too slow so I changed to parallel scanning. After an hour of wrestling with the code and many errors later it still didn’t work as I thought it was fixed by getting the scan done faster. Then found out that I had to put scanning in a background thread and this finally allowed the UI to be responsive during scanning.