That is not the Filter bar. The Filter bar is at the top of the screen. What you are showing is part of the Filmstrip. Collapse the Filmstrip and the bar you are showing is hidden.
That space is also in the real Filter Bar right click menu too. But IMHO there shouldn't be a right click option (menu) for the filter bar. Kind of pointless as the options are already in the filters icons. Why even right click on one of the icons.
When clicking on it the photos are "Filtered" so it is a "real" filter bar. The top filter bar is ONLY available in Library Grid view. The bottom filter bar is available everywhere. The setting in the two filter bars sync together.
I agree with you 100% that the right-click popup menu for "edits" and "labels" are kind of useless but the right-click popup menu for the "flags" is a lot faster and more intuitive than clicking away at the three icons to get what you want and is the only popup I use on this bar. I just noticed this.
Its not a big issue but makes it look like something is missing.
Lightroom Classic 8.4 was released today and contained a fix for this issue. Please update to 8.4 and verify that you are no longer seeing the issue. Thank you!