"Show notifications about detected indents" doesn't appear to work

I'm using IDEA 2017.3.1. I noticed that I haven't seen the notification come up to let me know that the file I've opened uses a different indentation scheme than what I've configured in my settings. Has it stopped working?

I've checked the "Detect and use existing file indents for editing" and the "Show notifications about detected indents" checkboxes in my Code Style settings. My project uses EditorConfig; it is set to use spaces, as is the code style settings for each of the relevant file types in IDEA. Yet when I open a file that's indented with tabs, I don't see the notification. I don't see it when I open a file that's indented with spaces either.

Will EditorConfig change the behavior of this notification in any way? I've tried enabling/disabling EditorConfig but it doesn't seem to cause the notification to appear.