I've looked at the eclipse log and it looks fine.

What is strange is that I realised it is not so much eclipse verison dependent as it is workspace dependent.

Eclipse 3.6 -->pointing to working workspace

Eclipse 3.5 -->pointing to non working workspace

As soon as I switched workspaces 3.5 started encountering the error and 3.6 started to work.

So naturally I proceeded to copy the working project over to the non working  workspace, but it still did not work!

So I tried creating a new workspace on both platforms and neither of them works.

Now I'm guessing it must be some type of config for the plugins in the specific workspace? But I find it strange since both of them are fresh installs.

Ok I've narrowed it down to one file - this is what I did:

1. I created a fresh java project on Helios

Then I created a test xhtml file

Result: Content Assist Does not work

2. I restarted Helios and opened it again

Result: Content Assist Does not work

3. I opened Galileo and open that same workspace and file

Result: Content Assit Works!

4. So I then proceeded to open this same file and workspace back in Helios

Result: Content Assit Works also!

I took snapshots of the files in step 2 and 3 and did a diff.There was a difference between .\.metadata\.plugins\org.eclipse.core.resources\.projects\***\.indexes\properties.index

So what I did was repeated step 1 and 2 with a different project name - and then i proceeded to copy the properties.index file over to this new project location and guess what?

Result: Content Assist Works!

So the workaround at the moment seems to be opening up the project in galileo and then reopening it up in helios.