Update (Jan 2017) FlashForge seems to ship the 2016 models with a new dome that is made of a single piece. This is an improvement over the older version which as made from flat sheets of clear plastic attached by screws. However, the new dome still use the same T shape cut in the back for the filament tubes. The Makerbot dome described here has a better tube path IMO since the tube rise inside without any cut in the back of the dome.
Update (Feb 2016): Humanisticnick@ reported that this dome worked also with the FlashForge Creator Wooden: "I just needed to trim down my filament guide tubes".
This thing describes an improved dome for Flashforge Creator Pro 3D printer. This dome has a few advantages over the stock one.
You can purchase MakerBot Replicator 2X Acrylic Dome Cover here: http://store.makerbot.com/parts-accessories/replicator-2-2x/x1-rep2x-top-enclosure.html . The Makerbot dome has a different shape at the bottom so it doesn't fit into the opening of the Flashforge case. To held it in place I used two rubber coated magnets from Amazon CMS Magnetics® 9 lb Holding Power Neodymium Magnetic Hook Rubber Coated. Pack of 2 http://www.amazon.com/gp/product/B00IGHBD7I but they are not required and the dome stays in place without them. When placing the magnets, to avoid a high impact on the acrylic dome, place the magnets on their side and then turn them slowly until their surface is in full contact with the dome.
I am also using a modified filament tube holder at the back of the case, it is slanted and moves the feeding point closer to the center of the spool. You can find it's 3D model in my account here as well.