What you are seeing are not ghost notes but more a poor choice of symbol by guitar pro in the guitar tab line. When it comes to guitar tab there are no standards but more a common way of doing some things, Other things get made up by the creators of tabs and tabbing programs as tabbing evolves. The guitar tab line only provides partial information and needs to be read in conjunction with the music notation line to get the full information. In Guitar Pro the brackets in the tab line do not represent ghost notes as they would in drum tab. They are just a reminder that you should still be sustaining the note when crossing into the next bar or applying an effect (slide, bend etc.).