The current download version of JWSCL (rev 316) contains a memory leak in the method EnumerateSession of class TJwTerminalServer in unit JwsclTerminal.
The reason is a string variable in the local thread storage (LTS) (maintained by threadvar) that is not freed automatically by Delphi. The new version uses a widestring instead of string which fixes the problem. The memory leak is fixed in the trunk version of JWSCL revision 325 or newer.
Download fixed code directly if you do not want to update to the latest subversion version.