I used to use TheBrain 6 and returned to download version 188.8.131.52 and find, as it seems have many others, that you can drag and you can drop but nothing happens. I have tried many of the suggestions and none works effectively except for file drops. I did however discover a workaround, using spotlight search on the Mac I can find contacts and drag them from there into theBrain. They arrive intact but the thought needs to be edited to the name, it is a long winded but so far more accurate and effective than the vaunted built-in service.
I do not get contacts returned in theBrain search facility even having accepted the dialog box to allow it. I am disappointed in the product so far as it appears retrograde from previous versions. I hope the move away from Java in mcaton's post of Jan 10 will be to something more fully functional for Mac users.