2505842 - Unable to change application, service, manager parameters in Config Tool

To change some parameters in config Tool under e.g. "applications", "managers" or "services" section. In this scenario enqu.port should be changed. While trying to set a Custom Value, the cursor does not appear in this field and no text is allowed to be written there:

SAP NetWeaver 7.1
SAP NetWeaver 7.2
SAP NetWeaver 7.3
SAP NetWeaver 7.3 EHP1
SAP NetWeaver 7.4
SAP NetWeaver 7.5

Final, Config Tool, configtool, offline config editor, expert mode, managers, applications, services, instance level, meta attributes, eny.port, ms.port, ms.host, enq.host, cluster, clustermanager, locking, lockingmanager, propertysheet properties, propertysheet, cluster_config, cluster config, kernel, workernode, clusternode_config. cannot be set, custom value, cutom falue cannot be set, flag, final flag , KBA , BC-JAS-ADM-ADM , Administration , BC-JAS-COR , Enterprise Runtime, Core J2EE Framework , Problem