If the cursor is inside the block containing the search scope and block highlighting is enabled,
highlighting of the search scope is then hidden by highlighting of the current block.

This can be seen in the attached file. I selected the two lines, then pressed Ctrl+F.
In the top screenshot, the cursor is outside the main() function block and the search scope is highlighted.
In the bottom screenshot, the cursor is inside the block, and the search scope isn't visible anymore, which is quite annoying.