If a person has permission to edit an issue, but not permission to assign issues in a particular project, if they then edit the issue, they can still see and change the assign field in the edit issue form.

As a workaround, I went into the edit_fields.jsp and changed

<webwork:if test="id == 'assignee'">
<jsp:include page="/includes/panels/issue/assignee.jsp" />
</webwork:if>

to

<webwork:if test="id == 'assignee'">
<webwork:if test="/hasProjectPermission('assign', project) == true">
<jsp:include page="/includes/panels/issue/assignee.jsp" />
</webwork:if>
<webwork:else>
<ui:component name="'assignee'" template="hidden.jsp" />
</webwork:else>
</webwork:if>

Is this workaround OK, or is it incomplete or will it end up breaking something else?