Description of problem:
When receiving emails with addresses separated by semicolons Thunderbird does
not wrap the To and CC lines.  This can cause the window drawing to mess up,
loosing the search field and right hand window components.  See attached png,
notice disappearance of; the search entry field, unread and total in the status
bar, columns after subject (this column was meant to take up about 1/3rd of its
pane), the activity circle at the top right and the failure to wrap the CC line.

Version-Release number of selected component (if applicable):
1.5.0.7-1.fc5 

How reproducible:
Very

Steps to Reproduce:
1. Send yourself an email with several (e.g. eight) To: addresses separated by
commas
2. View it and expand the subject line field to display the date and recipient
addresses
  
Actual results:
Several parts of the display are pushed out of the window

Expected results:
Window layout should not be affected other than showing the extra information