Created attachment 129392 [details] Screen copy macOS 10.14.6 Kstars 3.4.3 Menu "Configure toolbars" Adding any element in any toolbar does nothing. The element is not added. Whether toolbars positions are locked or not.
Are you sure this is 3.4.3 ?
Created attachment 129396 [details] Kstars version screen
So this is a slightly out of date build... let me see if I can ask Robert to build a new one soon.
3.4.3 is what you get when you download the macOS version :-)