I am very fond of the option “Duplicate current row” but for some reason this option is always disabled on my local MySQL server. It works perfectly on our remote server but when I duplicate a database on my local server the option is never alvaliable (even when I directly edit tables).
Please check if you have connected to the server with the ‘Read-Only’ mode enabled. You can verify if the title bar of SQLyog has the text “Read-Only” appended at the end of the connection name.
Send us a screenshot of the window where we can see the problem you are facing. Also, tell us your SQLyog version.