In Advanced Settings -> Moving & Resizing I use ctrl for Move and fn for Resize. Move works fine but Resize has never worked very well and seems to be getting worse, for iterm2 windows. It is hard to be precise at all. I have the old style magic trackpad and a 5k imac with external monitor. I tried changing pixel threshold to 0 and 10 from the default of 2 and it did not help. Any ideas?
Never mind. I finally went through all the iterm2 settings and found one at the very end of the last tab of settings. "Terminal windows resize smoothly". I changed it to yes and now everything is fine. This has been bugging me for years. Sorry for the bother.