I'm new to the Arduino IDE but I find the way it handles the leftmost tab (sketch) a bit odd. From what I can see, the filename (sketchbook name) is directly linked to the name of the first sketch. You can add or delete other sketches to/from the sketchbook but if you delete the first sketch it deletes the entire sketchbook. If you read my thread here http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1192321284 you'll see how I lost a bunch of code this way :).
I think it would be nice to be able to name the sketchbook independently of the name of the first sketch and to be able to delete any sketch in the file, including the first one, without affecting the rest of the file.
It would also be nice to be able to move tabs around to rearrange them but that's a separate issue.
Anyway, not sure if this is easily changed, just throwing it out there. Now that I know this behaviour, I can deal with it, but I wouldn't be surprised if other noobs go through the same thing when they first start using the program.
It's an interesting point, but I'm not sure Arduino is the best place to change this. The behavior comes from Processing, and I'd rather stay consistent with them - both for interface consistency and ease of implementation. You might want to suggest it to the Processing guys though.
I also found out that I was using tabs incorrectly. I was under the impression (or assumption) that the tabs would be treated as completely separate programs that could be compiled independently of each other. For instance, for my robot project, I have 2 Arduinos; one controls the servos and reads an ultrasonic ranger and the other drives an LCD display. I thought that I would create one file (sketchbook) for the entire robot project that would contain multiple tabs (sketches) with separate programs for each Arduino (and possibly other test programs as well).
After doing a little research on the Processing site, I found that all the sketches in a file are compiled together (unless they're hidden) so I'll have to create separate files, and have separate instances of the IDE open, for each of my programs. This was just misinterpretation of the program function on my part but to my knowledge this is not well documented on the Arduino site. Perhaps the “Environment” help page could be updated to include this information similar to the Processin page here: