Enable Auto Assist in eclipse ide

A while ago I disabled this feature and now I want to use it again. I went into Window->Preferences->Java->Editor->Content Assist and reenabled the "Enable Auto Activation" . It is set to a default 开发者_如何转开发of 200 ms and the . as the auto activation trigger. I restarted eclipse and it does not auto assist. I press the . key after R.layout and nothing happens. Ctrl +Space says there are no matching templates. What am I doing wrong so that content assist is not popping up.

Thanks

Is your Java source file in a Source Folder of a Java Project?

I had a problem like this in MyEclipse 10. It quit giving me the possible options when I typed "classname.". I reloaded MyEclipse with the "-clean" option (see below) and the problem went away.

e.g. Start>Run "C:\Program Files\Genuitec\MyEclipse 10\myeclipse.exe" -clean