Using V2009.5:

Let's say you work on a tune...

1. You make a bunch of changes.

2. You then choose File/Open, and you get a dialog box that asks "Save before closing?" and you choose "Yes."

3. When the Save As dialog appears, you decide to save it later, so you select "Cancel."

4. At this point, if you choose to open a new file, there will be no warning message, and any changes you have made will be lost.

BIAB shouldn't clear the "needs saving" flag until the file is actually saved.

I've sometimes gotten to step 3, thinking I'm in the File/Open dialog, not realizing the error until it says "The file already exists..." When I answer "No" when it asks whether I want to replace the file, I get to step 4.

Hope that helps.