I think that you hacked your comm.jar file in order to reverse the position of those two context menu items. The "Open link in new window" is the defaul setting. This is the hack, as posted in uFAQ:
How to get "Open link in new Tab" at the top of the right-click menu
In C:\Program Files\Netscape\Netscape\chrome, copy comm.jar, after first backing up the file.
Rename the file com.jar.zip, and unzip in a temporary folder
Open the file contentcommunicatorcontentAreaContextOverlay.xul in Wordpad, located in the Communicator folder.
Change the position of these two sections to look like this.