I have a requirement that a work item holds more than 100 attachments. But when I click on Advanced I see only 100 attachments and others are not showsn. I tried changing CoverattachmnetListEmbed and AttachmentListEmbedin Link-Attachment class, but of no use.
The standard section Work-.Attachments supports the Add button to allow the user to add attachments. This section includes the standard section Work-.AttachmentListView (not auto-generated) which executes the standard list view Link-Attachment.AttachmentList.ALL. Although no fixed limit exists on the number of attachments that a work item may have, the standard list view displays a maximum of 100 attachments.
To customize the presentation, override the auto-generated sections or the list view rule. (Do not override the Work-.AttachmentListView section unless you are making advanced changes.)
Below pdn link talks about the customizing the attachment display: