When you open a resource for editing, for example by double-clicking it in the EST Project Explorer, the default editor associated with that resource opens in the editor area of the current perspective.
The service flow project tools include editors that you can use to browse or edit resources that you have imported or created in the development environment (see Figure 1).

The host editor acts as a host system emulator, a screen operations recorder, and a flow recorder, and an importer (through its screen capture feature).
You use the host editor as a means to access terminal application resources for the purpose of capturing and recording an existing business function of a host-based application.
To use the host editor, you must set certain parameters that specify the connection properties. These connection properties are used to access the host system, which displays in the editor area of the service flow project tools.
Connection properties are stored in a host connection file, which is one of the terminal application resources associated with a service flow project.
Many existing host system applications (CICS® IMS™ and others) use BMS maps for 3270 screen output. This means that the server application can use data structures corresponding to named fields in the BMS map rather than handling 3270 data stream directly. The Assign BMS field names feature allows you to select a BMS map that defines a previously imported/captured screen.
The screen message editor allows you to view and modify the definition of a 3270 or 5250 application screen that you captured using the screen capture operation of the host editor.
You use the screen message editor to add recognition criteria (screen descriptions and descriptors) to facilitate how the screen messages are used at run time to pass data into, through, and out of the service implementation.
Screen messages are stored in .sfmxsd format, in a Messages folder within the terminal applications subproject that is associated with a service flow project.
The screen operations editor allows you to either modify the contents of an existing screen operations file or to create a new screen operations file.
Screen operations are stored in WSDL format, in an Operations folder within the terminal applications subproject associated with a service flow project.
The operations editor is the default editor provided by the service flow project tools for building the logical representation of an interface (WSDL operation).
The operations editor serializes the interface as a .wsdl operation with references to the .sfmxsd messages.
The flow message editor is the default editor provided by the service flow project tools for editing nonterminal message definition (.sfmxsd) files.
The editor is started in the editor area when you open an existing message file in the service flow project view or when you create a new message file using the New Message Definition wizard.
You use the flow editor to create, define, and refine the graphical representation of your service, including setting properties for individual flow nodes.
You start the flow editor in the editor area of the workbench when you open a flow (.seqflow) file in the EST Project Explorer. The editor area is where you select built-in and user-defined nodes, and the connections between them, to define a flow.
You use the mapping editor to define the mapping of structures or fields containing data from an input source onto output structures or fields in a target.
You use the flow ESQL editor to edit ESQL (.sfesql) files. In service flow projects, you use the flow ESQL editor to customize conditional expressions in Switch and While nodes.