https://online-help.sageerpx3.com/erp/12/staticpost/x3-script-keywords-glossary/

More importantly, where did you found the script that used the keyword: `setmode`?

Good day, Setmode is used during the import of data using an import template. It is used to change the mode of certain masks/variables events during the loading of data from the file to the screen. Normally there is no need for you use or change it as it proprietary to Sage X3 system calls and will generally be added where needed by the generated WW* source code of the import template. Its also legacy commands, hence why it is not in the help file. 

Hello, thank you for your answer. What do you mean by: "[...] change the mode of certain masks/variables events"?

I am reading IMPSMOS script (import for "miscellaneous issues", object SMO) and in fact the only thing I can notice is that if I comment out

Setmode INBAFF,IAFFCOD,IAFFMASK,IAFFCHP,IAFFIND,IAFFTXT,IAFFRANG,IAFFOPT1,IAFFOPT2
[...]
Setmode

dialog boxes (infbox etc.) start to work, otherwise they don't.

Hello, I found that on IMPSMOS script (import for "miscellaneous issues", module stock, object SMO)

It enables/disables the screen UI "Onevent" triggers which the user normally receives when data is entered through the UI. It allows for data loads to be streamlines making them more efficient.