Since 2.1 we added the possibility to limit the number of "designers" (page editing, article editing, edition editing, tracking, GNXCapture, publishing) a group can use in the same time.
The gn4:group object has a new attribute, called processLimits, where to specify the number of max licences for each designer (0 or missing = unlimited, which is the default).
The same attribute is computed in the gn4:user object, considering the values configured into all the groups that contain the user. For example:
<user>
. . .
<processLimits>
<item processType="pageDesigner" max="2"/>
<item processType="editionDesigner" max="5"/>
<item processType="TracyDesigner" max="22"/>
<item processType="GNXCapture" max="32"/>
<item processType="publishDesigner" max="34"/>
</processLimits>
</user>
If the user belongs to a group which has already reached the designer limit, then he cannot open more designers (even if there are available licenses in the system yet).