Windows – How Search File Content in Windows 8 File Explorer

I'm stumped as to how the search function is Windows 8 File Explorer is supposed to work.

I'm trying to search the content of some text files under a sub-folder of My Documents. In File Explorer (from the desktop) I've typed the search string in the search box. No results. I know that multiple files in the sub-folder contain the text I'm looking for; I opened a couple just to check.

I then went into the Advanced options on the File Explorer Search Tools ribbon bar, ticked File contents, then repeated the search. No results.

I then Googled the problem, which suggested I should index the folder containing the files I wanted to search. So I went into the Search Tools ribbon bar > Advanced options again, and clicked on Change indexed locations. I discovered that all the sub-folders of My Documents are being indexed already (and I double-checked that particular sub-folder was being indexed).

I thought perhaps the text I was searching for, "import" (without the quotes), might have been a reserved word or something so I tried searching for other text I knew appeared in multiple files, "datetime". Still no results.

Any ideas about what I'm doing wrong and how to get file content search working?