Nah it's not any of your plugins. It's just firefox properly rendering 600 characters worth of width in the textbox. It's missing the .editor class, and hence not receiving the proper max-width property that class carries:
<textarea tabindex="1" name="message" rows="7" cols="600"></textarea>
CSS:
#quickReplyOptions form textarea {
height: 100px;
margin: 0.25em 0 1em;
}
index.css?rc3 (line 1933)
textarea {
font: 100%/130% verdana,Helvetica,sans-serif;
}
index.css?rc3 (line 91)
input, button, select, textarea {
background: none repeat scroll 0 0 #FFFFFF;
border: 1px solid #7F9DB9;
color: #000000;
font: 95%/115% verdana,Helvetica,sans-serif;
padding: 2px;
}
index.css?rc3 (line 68)
Inherited frombody
body, td, th, tr {
color: #666666;
}
index.css?rc3 (line 37)
body {
font: 12px/130% Tahoma,sans-serif;
}
index.css?rc3 (line 23)
Box Properties:
width 4057.98px
height 100px