@elextr interesting… I usually see this still using separate source compiled conditionally with a common header defining the interface. But OK, so you have a case where there is no way to know but having complete knowledge of the whole project tree -- which we won't have (well, a plugin like projectorganizer *could* look at all the files, figure out the includes and make a slightly more educated filtering guess, but it'd still be a heuristic without knowing the real build settings and all).
But I agree with @techee, the filtering is useful to lower the amount of irrelevant suggestions in most situations, so we have to find where to draw the line. Or we go the Geany way and add a setting? :smile: