You don't have to exit your mission man, just place the addon in that current mission next to you, then hit preview, look at it, learn it, then go back to the editor, its really simple. A program to view it would also be pointless and make it even more work, since it would have to be external, causing you to minimize OFP completly, then your program would have to temporarily decompress the pbo (which isn't even possible while OFP is running, since the addon is in use), then open the models in something similar to bulldozer. All this would take much much longer than simply previewing it in the editor. This thread is pointless I don't see why its even worth arguing any more.