Might be this setting:
Enable filtering out of sub-folders in Flat View. By default the quick filter (i.e. the filter set by the Filter Bar) is not applied to folders when the file display is in Flat View. The reason for this is that when a folder is filtered from the list, all its contents are automatically filtered as well, and this may lead to undesired results. The Filter Bar has a checkbox option displayed when the file display is in Flat View mode that lets you turn folder filtering on or off, and you can use this option to control the default state of that checkbox (that is, if you normally do want the quick view filter to apply to folders as well as files in Flat View, turn this option on.)
See also here.
Otherwise, I'd rather start a new thread.