package explorer > View > Flat doesn't work; buildpath Libraries disappeared

Question

Can anyone solve this mystery? Until recently (not sure exactly when but suspect a few days or week, certainly before today when I installed the TestNG plugin), my Eclipse Helios has been fine. Then suddenly it went wacko. 1) All my Build Path Libraries have disappeared. I noticed this last week. When I put them back in, click ok, then go back in to that window to see them, they again have disappeared! Unfortunately, this is very reproducible. 2) It lost the ability to show the "flat" View in Package Explorer. I didn't do anything on purpose to change any settings and Flat still shows as selected. I also looked at the View filters and they seem ok.

I didn't notice any change earlier bz Eclipse continued to launch showing where I had left off. I have a Java project, over a year old, and it still seems to know it is a Java project. I've been editing and building away until I just happened to notice these things (while installing the TestNG plugin today) that are now going to cause me a lot of grief. - Our build system is different - building is with a makefile system on the command line. It hasn't changed substantially in over a year either. I use Eclipse to edit (no automatic building), sometimes debug (but not for a few weeks), and soon hope to use TestNG.

My Java perspective: I'm not sure what Reset Perspective actually does so I did not do that. Package Explorer > Fast View is not selected.

A co-worker's Eclipse is running fine (I'd helped him set it up about a year ago) showing the Flat View and all the Build Path Libraries. Thus, it is me (or perhaps my environment?) and not the wider environment we all share (Linux).

I've tried to read all relevant posts but no suggested solution that I've read has solved the issue.

I sure hope someone can dream up an answer! Thanks!

Answer 1

UPDATE: I had to create a new project. My problem with the desired flat view of the Package Explorer vs. the hierarchical view displayed had to do with Configure build Path and the packages I chose for Source. Any package I chose to Use As Source Folder would then appear in a hierarchical manner below all the packages showing Flat.

Now I can make a Flat package transform into a hierarchical display but have not figured out how to make a package that is displayed hierarchically transform into Flat display.