I can second this. Field is reset when you come back to edit.
There’s a bug in line 1204 with 2 value attributes. Change this:
<td><input type="text" name="cpt_custom_post_type[capability_type]" tabindex="6" value="post" value="<?php if ( isset( $cpt_capability ) ) { echo esc_attr( $cpt_capability ); } ?>" /> <a href="#" title="The post type to use for checking read, edit, and delete capabilities" style="cursor: help;">?</a></td>
to this:
<td><input type="text" name="cpt_custom_post_type[capability_type]" tabindex="6" value="<?php if ( isset( $cpt_capability ) ) { echo esc_attr( $cpt_capability ); } else echo 'post'; ?>" /> <a href="#" title="The post type to use for checking read, edit, and delete capabilities" style="cursor: help;">?</a></td>
Looks like this has not been fixed as of version: 0.7.2.
Definitely fixed in 0.8, which will be out soon.
Great news, and no problem — just reapplied the fix. Thanks for a great plugin, Michael.