IMP Configuration

conf.php

This is the file where all server-wide settings for IMP go. It is supposed to be generated through the web interface.

User Capabilities and Constraints

$confuserselect_view

If DIMP and MIMP are installed, the IMP login page displays a drop down list that allows the user to pick the preferred webmail view. This decision is stored in a browser cookie, so that the selected view is selected by default the next time the user logs in.
With the configuration setting $conf[user](user)[select_view](select_view) you can disable the drop down list.

There is no setting to make one of the views the default for user that have not logged in and picked a view yet. You can achieve the same with adding the following lines to config/conf.php though:

if (!isset($_COOKIE['default_imp_view'])) {
    $_COOKIE['default_imp_view'] = 'dimp';
}