If you do a FILE -> LOAD you will get a prompt "Load File Into Current Window".
If you do a FILE -> OPEN you should get a prompt "Edit New File".
If you’re doing a FILE -> OPEN and you don’t get a "Edit New File" prompt but instead get a "Load File Into Current Window" prompt, then there are a few things we can check:
Go to TOOLS -> CUSTOMIZE -> GENERAL -> KEYS/COMMANDS,
look for the "File Operations" section near the top, look for "Open File", select "Open File" and click "Edit". The command line for this, which is shown at the top, should be [code:3ling7ue]LoadFile /E=1[/code:3ling7ue]
Exit that back to the CUSTOMIZE menu, and select MENUS.
Select MAIN and click ‘Edit’.
Go to the top of the resulting Edit Menu Set "Main" dialog, FILE should be the top line, indicating this is the FILE menu, and OPEN should be right below it, indicating this is the FILE -> OPEN menu option. Select that and click ‘Edit’. In the resulting EDIT MENU ITEM dialog, the command should say "Open file", and if you click the "…" button to the right of that field, you should get the Open File command we looked at earlier.