Disable top toolbar element overflow via about:config in single toolbar mode

[Evthestrike]

It would be very useful to me to have an about:config toolbar setting to disable elements overflowing into the >> menu in single toolbar mode. This setting should also prevent pinned extensions from returning to the list in the unified extensions button.

This overflow happens when the sidebar is resized to be too small to contain all of the toolbar buttons. The reason I want this setting is to write a CSS mod that allows the top toolbar elements to wrap onto a new line of buttons if there is overflow. This would also allow easier implementation of a mod that would allow something like the pinned extensions behavior in Arc.

It would also solve my problem to implement the overflow menu like it is with bookmarks where the hidden elements are not removed from the DOM but instead have visibility: hidden.

Any discussion or questions is welcome!