You should see one "x" followed by two blank lines. The blank lines should be the same height. The second line must be the same height as the first. See: <rdar://problem/3959727> REGRESSION (Mail): Style not preserved on blank lines
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>
execDeleteCommand: <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"><br></div>