The LLBLGen Pro designer can generate sourcecode automatically when you save your project, in the background. To enable this, go to the Project Settings and check the setting 'Automatically generate source code on project save'. This feature works the same as if you're manually generating code, it executes the same tasks.
If you haven't generated code for a project before, it's likely the code generation tasks aren't properly configured yet. To do so, either
generate code manually or configure the tasks without generating code by selecting from the main menu:
Project -> Configure Code Generation Tasks.... For further information about how to configure these tasks,
please see Configure a Code Generation Task.
In the status bar there's an identication button, which can either be (Automatic code generation is enabled, tasks have been configured properly) or (Automatic code generation is enabled, there are errors in the code generation tasks so no code will be generated). Clicking it will open the code generation tasks viewer to configure the code generation tasks. Hovering it will pop up a tooltip which will describe the current state of the automatic code generation feature and what will happen when clicking the button
If automatic code generation has been disabled, the icon is greyed out/dimmed.
Be sure to check out the auto-clean up feature of the designer, as it is especially useful with automatic code generation.