Hi Mohammad
Some points about the list widget:
* If the “filter” attribute is not present then a default of “[!is[system]sort[title]]” is used
* If the list widget is completely empty (ie only whitespace between the opening and closing tags), then it behaves as if the content were a DIV or a SPAN containing a link to the current tiddler (it’s a DIV if the list widget is in block mode, or a SPAN if it is in inline mode)
* If the “template” attribute is not present then the content of the list widget will be used as the template, unless the widget is completely empty in which case a default template is used
It’s is itself more complex than we’d like, and interacts with some other complex concepts (eg inline vs. block) and has some weird edge cases, and bugs.
A useful tool for exploring this stuff is to use the “Internals” plugin to view the parse tree for each example.
This one is a bug, I think. The parser is seeing it as a widget/element containing a paragraph containing a new line, where it should be parsed the same as the next example.