Eclipse IDE not warning me if file has been modified outside its environment

My eclipse environment doesn't load开发者_如何学Python or warn me if the file has been modified outside its environment, instead its asking me if I should overwrite the one of disk with my changes. This used to work properly, but not sure why its failing now.

As far as I recall, this is the 'normal' behavior, and this is the warning that you get if the file on disk was externally changed and you have made changes to the source in an opened editor.

There is one thing that may help (at least on stratup): Go to Window -> Preferences and click General->Workspace. Make sure that 'Refresh automatically' is check (by default it's not).

Cheers