You should see one "x" followed by two blank lines, then one more "x". The blank lines should be the same height. The second and third lines must be the same height. See: <rdar://problem/3959727> REGRESSION (Mail): Style not preserved on blank lines
x


x
execInsertParagraphCommand: <div id="test" class="editing">x</div><div id="test" class="editing"><br></div>
execInsertParagraphCommand: <div id="test" class="editing">x</div><div id="test" class="editing"><br></div><div id="test" class="editing"><br></div>
execTypeCharacterCommand: <div id="test" class="editing">x</div><div id="test" class="editing"><br></div><div id="test" class="editing">x</div>
execFontSizeCommand: <div id="test" class="editing"><font size="7">x</font></div><div id="test" class="editing"><font size="7"><br></font></div><div id="test" class="editing"><font size="7">x</font></div>
execInsertParagraphCommand: <div id="test" class="editing"><font size="7">x</font></div><div id="test" class="editing"><font size="7"><br></font></div><div id="test" class="editing"><font size="7"><br></font></div><div id="test" class="editing"><font size="7">x</font></div>