CODESYS Automation Alliance I doubt that this organization still exists in any form.
Use declaration with ARRRAY [1..x] instead of ARRAY [0..x]
Use ARRRAY [1..x] instead of ARRAY [0..x]
https://forge.codesys.com/prj/codesys-example/selection-manag/home/Home/
Seems like you use SIZEOF as size, but you need to use LEN as size of data which you want to write.
Seems like you write SIZEOF bytes, but you need to write LEN bytes.
https://content.helpme-codesys.com/en/libs/VisuElemBase/Current/Public-Parts/Interfaces/IMouseEventHandler.html https://content.helpme-codesys.com/en/CODESYS%20Examples/_ex_visu_event_handler.html
Thank you.