I just went through a cleanup and organization of my Desktop as it was getting a bit messy. Part of that mess was the number of TM Project files that started to collect there. I decided to put them in a folder and then drag the folder to the Dock so I could get a popup of the contents, the same as the Documents and Downloads folder.
After I did this I found that that Textmate would open, but the contents where in red coloring and not available to me. After some looking I found that files contained the path to my files relative to where the Projects file was created. I thought that at this point it would be faster to simply edit the files in Terminal with vi rather than re-create everything, and also better since I would retain all the settings that were embedded.
As a test on one of them I changed the path from a relative path (../ Sites/foldername) to an absolute one (/Users/myname/Sites/foldername) and it opened everything the way I expected. But after I closed the project in Textmate, I found that the path had once again reverted to relative again (../../Sites/foldername). I ended up changing a dozen or more files anyway, and now all is good, but I can't imagine what the effort would have been if I had many, many projects.
So I guess I am wondering why this is the behavior, and why Textmate can't use an absolute path which would make management of the Project files a lot easier. And before someone asks, I do a lot of online testing of different installations and I like having direct access to the Projects without having to navigate to them in the Finder and finding them in the actual folder name. I also don't have the Project file(s) cluttering up my site files either.