I found the solution for line break.
first. Open the file.
"/wp-includes/js/tinymce/plugins/wordpress/editor_plugin.js"
line 243:
content = content.replace(new RegExp('<p>(\\s| )*</p>', 'mg'), '');
-->
// content = content.replace(new RegExp('<p>(\\s| )*</p>', 'mg'), '');
line 297-300:
content = content.replace(new RegExp('\\s*<p>', 'mgi'), '');
content = content.replace(new RegExp('\\s*</p>\\s*', 'mgi'), '\n\n');
content = content.replace(new RegExp('\\n\\s*\\n', 'mgi'), '\n\n');
content = content.replace(new RegExp('\\s*<br ?/?>\\s*', 'gi'), '\n');
-->
//content = content.replace(new RegExp('\\s*<p>', 'mgi'), '');
//content = content.replace(new RegExp('\\s*</p>\\s*', 'mgi'), '\n\n');
//content = content.replace(new RegExp('\\n\\s*\\n', 'mgi'), '\n\n');
//content = content.replace(new RegExp('\\s*<br ?/?>\\s*', 'gi'), '\n');
line 572-588:
pee = pee + "\n\n";
pee = pee.replace(new RegExp('\\s*', 'gi'), "\n\n");
.
.
.
pee = pee.replace(new RegExp('(</?(?:table|thead|tfoot|caption|tbody|tr|td|th|div|dl|dd|dt|ul|ol|li|pre|select|form|blockquote|address|math|p|h[1-6])[^>]*>)\\s*
', 'gi'), "$1");
pee = pee.replace(new RegExp('(\\s*</?(?:p|li|div|dl|dd|dt|th|pre|td|ul|ol)>)', 'gi'), '$1');
-->
//pee = pee + "\n\n";
//pee = pee.replace(new RegExp('\\s*', 'gi'), "\n\n");
.
.
.
//pee = pee.replace(new RegExp('(</?(?:table|thead|tfoot|caption|tbody|tr|td|th|div|dl|dd|dt|ul|ol|li|pre|select|form|blockquote|address|math|p|h[1-6])[^>]*>)\\s*
', 'gi'), "$1");
//pee = pee.replace(new RegExp('(\\s*</?(?:p|li|div|dl|dd|dt|th|pre|td|ul|ol)>)', 'gi'), '$1');
But some problem left yet.
Good luck to you.