To Reproduce:

1. Create a new script.

2. Delete/Change any object in the scene, click CMD/CTRL+Q and then Cancel in the 'Do you want to save' menu.

3. Edit & save the script in MonoDevelop.

4. Observe that it is not recompiled or even updated in inspector.

5. You can click reimport or refresh on it and the script will be recompiled, but it won't happen automatically after further edits you'll have to reimport every time if you don't restart Unity.

Can be reproduced in all versions since at least 4.3.4f1.