When using the "Customise Menu" feature to change the toolbar icons, the changes are not reflected in the actual toolbar. No matter what extra icons I add to the toolbar, they do not show up. Changing the order of toolbar icons is not reflected either.
On a related note, what is this icon supposed to be?

It does not show up as one of the icons in the "customise menu" screen, and it is not the overflow menu since that's the three dots next to it.
Changes made to the toolbar using "Customise Menu" should be reflected on the actual toolbar. All icons on the toolbar should be explained, and show up on the "Customise Menu" screen in the same order and position they are in on the toolbar.
0.4.1 (WebKit 2.50.4) on Linux Mint 22.3 Cinnamon