when i'm working with the Calc program i noticed that the developers went with the interactive save icon approach.. the problem is, perhaps only in a spreadsheet, there are things that i can change that may not trigger the icon to be enabled again after i have saved.

example: 
i may freeze a portion of the window after my last save, and that action will not trigger the save button to become enabled again.


i think having an interactive save icon is cool, but when compared to the potential for bugs such as this, and the extra coding i'm sure had to be done to keep up with possible triggers to re-enable the button, i think just leaving the icon always enabled is the better more sensible option. it's on the user to keep up with whether or not they saved their work. when applications try to think for you, that's when things start getting weird. not being able to save after i just froze a portion of the spreadsheet is weird.