Contact Manager Add Bug

File:/var/www/html/admin/modules/contactmanager/Contactmanager.class.php:1823

Spent some time with a customer debugging this.
The steps to reproduce this are:

-Navigate to* Modules ->Applications -> Extensions -> Quick* create extensions.
-Create an extension (enter data, then Next, then Finish)
-If the user remains in the Extensions *module web page and needs to add another extension through the '*quick create extensions' the wizard is not incrementing the extension number based on the previous 'Extension Number' entered by the user.
If the user manually modifies the *Extension Number *and tries to create the extension the following error appears:

Undefined variable: id
File:/var/www/html/admin/modules/contactmanager/Contactmanager.class.php:1823

In order to workaround this there are two options:
-The user must *Previous *then *Finish *and the wizard creates the extension.
Or navigate to Admin>Modules -> Extensions -> quick create extensions.