Disable spell check for expressions.
<td colspan="2"><select bind="expressionPreviewLanguageSelect">$LANGUAGE_OPTIONS$</select></td>
</tr>
<tr>
- <td colspan="3"><div class="input-container"><textarea class="expression-preview-code" bind="expressionPreviewTextarea" /></div></td>
+ <td colspan="3"><div class="input-container"><textarea class="expression-preview-code" bind="expressionPreviewTextarea" spellcheck="false" /></div></td>
<td class="expression-preview-parsing-status" bind="expressionPreviewParsingStatus" width="150" style="vertical-align: top;"></td>
</tr>
<tr>
