Hi and thanks for all your work in building the Arduino IDE.
I found a big bug - the hard way.
I started Arduino.exe and the IDE opened and showed an empty document, "sketch_nov23a".
I clicked on File, Sketchbook and chose the recent project. (there was only one)
It loaded up in another Arduino window. I then closed the original sketch_nov23 empty window.
I worked on it for three hours and had my sketch running great.
I had to close Arduino temporarily to do something else. I closed the window and it asked if I wanted to save changes and I clicked Yes. It then closed down, but my changes WERE NOT SAVED.
I restarted Arduino.exe and my sketch was back at the stage it was three hours ago.
I have replicated this fault again. The fault does not happen if I leave the initial blank Arduino window open and then close that one last.
I am running a Windows XP machine with all straightforward options.
It seems as if the blank initial IDE window is a parent of the new window that is loaded and when the parent is closed the child window becomes orphaned.
Anyway, I hope this helps to improve the IDE. If you can't recreate the bug, I can make a screen-video of it and show you.