Problem
I cannot copy and paste a node from other files.
Solution
HARK-Designer can cut, copy and paste in normal operation.
Copy and paste can be enabled by the following procedure.
Click "File". Load the network file that contains the block to be copied.
Select the block to be copied, and click "Right click" -> "Copy "
"Right click" -> "Paste " at the copy destination
Also, you can use the following shortcuts:
Ctrl-c: Copy
Ctrl-x: Cut
Ctrl-v: Paste