When editor gui loads commands that have many new lines it becomes significantly less responsive - keyboard and mouse input (mostly noticeable by moving with arrow keys, or mouse) is processed after quite large delay, which gives bad editing experience.

The issue affects gui even when the edited chain only contains one command block.

I suspect that each textbox interaction may cause the command string to be rebuild internally, which could happen to be expensive process, although I have not yet profiled that (currently setting up the java and scala, when I will be done with that, I will try to provide some metrics)

Version used: 0.4.1 from Modrinth
Fabric loader: 0.14.19
Minecraft verison: 1.19.4

I've got the same problem. It seems like the FPS of the whole game drop significantly whenever you open the GUI of a command block containing many newlines, it is not just a delayed keyboard input.
(I'm using the mod version 0.4.3 from Modrinth on Quilt Loader 0.20.2 on Minecraft 1.20.1)

This should be fixed by commits 293d533 and 4ca0a1e.