if you go to screen options in the top right corner of your admin, under ‘Show advanced menu properties’ you should be able to then choose:
Link Target
this will reveal that option dropdown box below in your menu selection
Very strange. It seems like it is file related because I re-purpose another stylesheet from another theme and it works properly. But if I cut and paste the exact same header to the old stylesheet it breaks.
I have used winmerge to compare the file types, and they appear to be the same, carriage returns etc. I tried to upload using different formats through the ftp client and still does not affect.
So a quick solution is to resave an existing working style.css file and rename the parameters.
I am having the same problem. I will post a solution when I can figure it out.
