I have a Word document containing "fillable forms" made as "table of content controls".
There is one "envelope" content control which is locked, but contains nested content controls, some of which are the "filable" ones, i.e. are not locked.

Now, with the default settings Studio does not extract anything from the content controls at all...
It's necessary to set the "Process locked content controls", but then Studio extracts text from all controls, including unwanted from the locked ones :(

Here are some screenshots showing the document structure.
By default Studio extracts only the "Module", "Module Title" and "Module Information" strings which are just "plain text" outside of content controls.
After enabling the "Process locked content controls" option Studio extracts all texts including those in 'left column' ("Course Number", "Course Text", etc.), which are unwanted and a) pollute the project, b) must be manually locked to keep non-localizable texts intact.