When editing custom drawing properties, is there no way to scroll through your list of props, or advance to the next one in line, other than picking each one with a mouse click? Being able to Tab, or Space, or Enter to advance through.... similar to the attribute dialog box of old... would be quite handy. If the answer is no, I'll post it as a wish list item at AUGI.
There is no way to do this at this time in the Custom Properties. It is a good wishlist item. I would also recommend posting it with the Product Team.