the blinking caret indicates that the editor is actually focused. It means, when the user presses a key, the key event will be processed by the editor. The editor automatically attracts the focus when the user touches within its area. You can focus the editor also programmatically. For this purpose:
1. Open the component containing the embedded instance of the editor.
2. In Inspector window look for the member this. This member represents 'this' component opened actually in Composer.
3. Select the member this.
4. Now the Inspector lists the properties of this. Look there for the property Focus.
5. Edit the property Focus to refer the editor instance.
Following screenshot demonstrates it:
Now, the Editor is focused per default. For more information see the section: Keyboard events and the focus path.
I hope it helps you further.