One of my recent script, $lsbridge script that visualize vlan-filtering=yes (http://forum.mikrotik.com/t/example-of-automating-vlan-creation-removal-inspecting-using-mkvlan-friends/181480/1), is at 49Kb, currently. But at some point is was >64Kb as I added another set of helper functions… WinBox truncated the part above 64K, and saved the 1st 64Kb… no warning. Now I’d cut-and-pasted from VSCode, so /system/script was not main copy.
While I cannot fathom anyone editing a large (or really any) script using the WinBox dialog, the dialog will let you TYPE above 64Kb into the edit box… it just doesn’t save that part.