File | Settings | Build, Execution, Deployment | Debugger | - Live Edit
The page is available only when the LiveEdit plugin is installed and enabled.
The plugin is not bundled with IntelliJ IDEA, but it is available from the JetBrains plugin repository. Once enabled, the plugin is available at the IDE level, that is, you can use it in all your IntelliJ IDEA projects. See Installing, Updating and Uninstalling Repository Plugins and Enabling and Disabling Plugins for details.
|Highlight current element in browser on caret change||When this check box is selected, the browser highlights the area that represents the code you are currently editing in IntelliJ IDEA.|
In this area,
configure the way changes made to the code during a debugging session are applied.
Note that an update will now be performed only if none of the modified files have any syntax errors.