I would find it very useful to be able to config the display of username and password in the tree view, and in add/edit on an per entry version. I would envision options like use default, always show, never show, and these could be applied to username and password display in tree view and password display in edit/view. From a UI perspective I would really like to see an additional tab for the add/edit/view dialog called display options, where these options would be configured.
What would also be great if you could configure the number of characters of username and password that is displayed, and this could be use default or a number. I would use this to display the first four or five characters on some of my less important passwords as a memory prompt. I would use this paricularly for signing onto servers that do not allow pasted passwords.