In Construct 0.99.42, if I edit an event sheet - that is, for example, adding conditions, or removing events - and then choose to exit Construct, it will not ask if I want to save before exiting. It will instead lose the changes.
On the other hand, if I have deleted or moved an object in the layout editor, it does ask if I want to save before it exits.
(I can even move objects then alter an event sheet, and it will ask to save before exiting. It just doesn't seem to consider event changes as modifying the file.)
Also, if I open a cap, click a sprite, and add a new animation to it, I can close the cap without Construct asking if I want to save.
Even if I edit the animation frame's graphic, draw in it, and tell it yes to save the changes to the image, Construct won't ask to save when I close it, unless I reposition objects, etc.