Comment Text Box does not display in IE6 and 7

In IE 6 and IE 7, the comment box appears to be not showing when the "Comment on this issue" link is clicked, IF there is edited comment in the issue.

The steps of reproducing (this however is client data specific, see comment below for the data):

1. Add a comment on any single issue.
2. Edit the comment.
3. View the issue in IE6 or IE7, the comment box appears to be not showing.
4. Issue can't be added comment and it displays this JavaScript error:

Can't move focus to the control because it is invisible, not enable, or of a type that does not accept the focus

Tested with this JavaScript:

javascript: document.getElementById("commentDiv").style.display = "block"; void(0);

There is no such problem in FireFox.