I've been using Contact form 7 on a sidebar on my site. I just updated to the latest version and now it's overflowing wider than my sidebar. I didn't change any of the code.
Here's the page with the form.
Here's the code I'm using, which hasn't changed, and has worked for the last few updates.
So far I've tried specifying the width for the table and cells, and changing the character width for the text area, all of which has had no effect on the formatting. The only thing that has worked, and go it to fit within the sidebar is removing the textarea entirely.
<table>
<tr><td>Name:</td><td align=right>[text* your-name 25/]</td></tr>
<tr><td>Email:</td><td align=right>[email* your-email 25/]</td></tr>
<tr><td>Phone:</td><td align=right>[text your-phone 25/]</td></tr>
<tr><td>Subject:</td><td align=right>[text your-subject 25/]</td></tr>
<tr><td colspan=3>Message
[textarea your-message 29/6]
[submit "Send"]</td></tr>
</table>