FWIW & IMO - for the FM plugin, the language flipping issue is very far edge, hence not worthy of a new release. I don't use the Action Chain plugin so I won't comment on it.
However, the manner of dealing with 'invalid' menu items does warrant consideration. At the moment 'invalid items' are 'greyed out', however I find 'greyed out' items difficult to see in Dark Mode, the text remains bright white but with what might be a shadow effect. Not all items that can be added to FM have an icon, e.g. Choose Library->Quick Switch, hence that the icon is also missing is irrelevant.
How might an item become invalid?
- Because it refers to a plugin that the user has removed;
- Because the selected item label changed:
- Either in the calibre base e.g. the recent removal of the three trailing dots in Create/switch library...;
- Or in a optional plugin's item options menu, as occured in the View Manager a while back.
My preference would be that the 'invalid items' be dropped, with a short-lived message in the status line e.g. "FM items removed, use the Configuration tool to rectify". But having discovered the anomaly I'm unlikely to get bamboozled by it again, so… whatever.
BR