ID 580988 - Sequence revision comments cannot be deleted

Problem summary
Revision comments can not be deleted
 
Customer reported version
flix_7.0.2
 
Customer reported platform
windows10
 
Steps to reproduce
 
1)Save a sequence revision with comment

2)Edit the comment and try to delete it
 
Expected behaviour
The comment should be removed
 
Actual behaviour
The comment can be changed, but it can not be completely deleted
 
Workaround
Enter a single space character as the comment. It will look like there is no comment at all on the revision page
 
Reproduced by support
 
This bug has been reproduced in:
7.0.2
 
Unable to reproduce bug in:
6.6.2
 
Earliest version tested
6.6.2