Reported by TigerLilly.
The Identifiers tab of the Uses Clause Manager only parses .pas files found directly in the folders of the library path, the project's search path and a few others (project units, the IDE's Source folders, the search path favorites). The IDE's browsing path is not searched.
Component packages are often installed with only the folder of their compiled .dcu files on the library path and the source on the browsing path. Their units then appear on the Search Path tab, which also lists units for which only a .dcu file is found, but none of their identifiers appear on the Identifiers tab, e.g. TTMSFNCDataGrid from the TMS FNC UI Pack.
(In the original report the source folder turned out to be missing from the library path altogether; adding it there made the identifiers appear. The browsing path case was found while looking into it.)
Expected: a unit whose .dcu file is on the library path or the project's search path, and whose source is on the browsing path, contributes its identifiers.
Fixed in revision 5989.