select it manually with the mouse and use ctrl-c
and ctrl-v

then remove "copy code" etc. in the IDE

That's because the poster selected the Insert Code button, then pasted the code. That's the wrong method, people have to paste the code first, select it then click on the format button. But for me, I usually get the empty lines removed (unless they have white space in them). No perfect solution in the Zoho world.
As Chrisir said, when you have only one line number for the whole code, you have to manually select the code with the mouse (for long code, select the first few chars from the left, then Shift+Click at the end) and to use the good old Ctrl+C to copy the code (with issues if pasted in several parts...).

I didn't know that - it's not obvious. But I'll do it this way now.