QuickFolders integration: buttons on Current folder toolbar can be missing

[RealRaven2000]

While working on a theming feature for QuickFolders, I found a major flaw in the way the optional buttons from quickFilters Advanced preferences (that can be displayed on QuickFolders' current folder toolbar) are created:

these can only be added by quickFilters successfully if it injects these items after QuickFolders has generated the toolbar. QuickFolders has currently no way to tell quickFilters to recreate them when QF is disabled / updated or started after quickFilters has started. Which will lead to these buttons missing.

The buttons can be made visible from the quickFilters preferences window (by right-clicking the quickFilters Assistant button and opening the Advanced page):

[RealRaven2000]

To deal with the problem, we need to patch QuickFolders to notify quickFilters when it has injected its own current folder toolbar. quickFilters can then move the buttons from the (hidden) box in the main toolbar to the current folder bar. Also, when QuickFolders ends or is uninstalled / disabled / shut down for an upgrade, it needs to move these items back so they can be added again when QuickFolders is activated the next time.

Below are two patched versions that should work together. install quickFilters first to avoid having to restart.

quickFilters-wx-5.6pre44.zip
QuickFolders-mx-5.13.2pre27.zip

(To install, drag the zip files into Thunderbird Add-ons manager as always, without unpacking the contents)

[RealRaven2000]

Implemented in 5.6 - released 17/10/2022