Wow!

Now that I am understanding JEdit more I must say it is a wonderful editor.

Really impressive.

The Whitespace plugin works well for me (also jEdit 4.3pre5). The "show spaces" action toggles visibility of the configured types of whitespaces. There are 3 toggles for them (leading, trailing, ..)

There's no integrated function for toggling spaces. But You can create a toolbar button and assign any action or macro to it. To toggle all Whitespaces use the following macro (but toggle all types of spaces and tabs ON before):
whitespace.WhiteSpaceActions.toggleSpaceHighlight(buffer);
whitespace.WhiteSpaceActions.toggleTabHighlight(buffer);
whitespace.WhiteSpaceActions.toggleWhitespaceHighlight(buffer);

The display of wrap line and line ends is toggled in "global options | textarea". If jedit forgets any settings then try to delete jedit's settings directory.

Robert