When you publish app in Win7 VDI, open the App and then close it, the session won't logoff
This session can’t logoff the session manually in studio. The only option is to restart the VDA to allow users login again.
 

Caution! Using Registry Editor incorrectly can cause serious problems that might require you to reinstall your operating system. Citrix cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk. Be sure to back up the registry before you edit it.

Add the following registry key to fix this issue:

Under
Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Citrix\wfshell\TWI\
Create
IMEFlag
DWORD value: 0x4
Type       
DWORD value: 0x4

---

Problem Cause

There is an application window blocking the Citrix pre-logoff check
Normally we can identify the app and add to following registry:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Citrix\wfshell\TWI
Value Name:LogoffCheckSysModules
Type:REG_SZ

However, in this case, due to huge amount of applications are published, it is not easy to identify the problematic App that blocking the logoff