Relevant release:
NW04S SP14 and up (When Desktop Filter Feature First Exposed).
When using the Desktop Filter Feature and changing desktops at runtime (for example changing the URL alias from /portal to /portal/light ), the desktop might not be switched correctly and the user might not receive the relevant roles.

Other terms

Desktop Filter, Filtering, Entry Point, desktop, runtime, run time
Reason and Prerequisites

Prerequisites:
SAP NetWeaver 7.00 SP14 and up is installed.
Reasons:
- Using Filtering Entry Point feature.
- Changing desktops at runtime.
Solution

The problem was that switching URL aliases in the same session was not supported when the desktop filter feature first introduced, that caused some side effects.
The functionality was fixed in the versions describe below so now, when switching desktops on runtime, the user will get the correct desktop with the correct roles based on the filtering feature.
Versions that include the fix:
SAP NetWeaver 7.00 SP19 PL3.
SAP NetWeaver 7.00 SP20.
SAP NetWeaver 7.01 SP04 PL2.
SAP NetWeaver 7.01 SP5.