Bug 308097

If you edit a filter criteria tha is made semi-automatically, using the context menu option 'Create Filter > Filter on From...' on a e-mail, it will failn
Because you can't edit e-mail addresses in the Available Filters pae, you have to remake the filter once it's broken

Reproducible: Always

Steps to Reproduce:
1. Use an e-mail to make a filter based on the 'From:' field, using the shortcut menu option 'Create filter > Filter on From...' The Filter Rules dialog is opened with the skeleton of the filter filled in for you and the e-mail address shown in the Available Filters pane on the left timmediate after the colon i.e.
'<From>:e-mail@e-mail-address'. 
2. Edit the filter criteria in the right hand pane, add a space at the front, and remove it with the backspace key (or do any other edit of the text or a single character).  The e-mail address in the Available Filters pane now shows a leading space character after the colon i.e.
'<From>: e-mail@e-mail-address'. 
3. 
Actual Results:  
The e-mail as shown in the Available Filters pane seems to be what is used, not as shown in the Filter Criteria pane. The match is exact, including the leading space character, which is never present in the e-mail address used to create the filter, so the filter always fails

Expected Results:  
The Available Filters pane should not add a leading space character to email addresses when the Filter Criteria are edited. It should duplicate any editing done in the Filter Criteria pane. In the example given, it should follow the backspace key, and remove the leading space from the e-mail address

There are any number of bug reports where this may be a contributory factor