wysiwyg editors malfuction First, the problem:
I create a new Basic Page content with simple text and a couple of carriage returns, for example: 

this
is
my
content.

I save the content using "Filtered HTML".  When I then try to edit that content (still with "Filtered HTML") the content in the body of the editor has lost all the carriage returns (and formatting if applied) and looks like this: 

this is my content.

If I save this content it still looks like the above.

This does not happen with the WYSIWYG module installed but no editor added.  When I add TinyMCE and configure with any buttons, then I get the above problem.  This also happens with CKEditor.

I've tried three new clean installs of test sites (two on my local server and one remote) and I get the same results when I try to configure an editor with WYSIWYG.

The only non-core modules I have installed are chaos tool and WYSIWYG.

Very perplexing.  Can anyone help?
Put &lt;br/&gt; in view source mode of your field as your line separators.