6 MONTHS! COLD TURKEY? YOU CAN'T BE...
This is 100% the right decision. I'll miss the new features for a while but I understand the commercial imperative.
Perhaps there's a middle road?
XYplorer already has customizable user buttons with dropdown menus.
I suspect most users who add a user button with a single action for the left-click don't waste the opportunity to add a right-click menu.
I typically add all related commands (and scripts) to these drop down menus. After adding all available custom buttons I have most of the menu items available from the toolbar.
The point is, you can add your own text next to each item in the dropdown lists and this can be in any language you want.
Suggestion:
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Tweak the existing toolbar functionality to allow the main menu to be accessed via toolbar buttons so that 12 toolbar buttons replace the menu.
The tweaks
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1. Remove limit on number of custom user buttons
2. Add additional toolbar (row)
3. When "label" is used in the icon field make the menu button width automatically grow to match the length of label text. Otherwise provide icons to represent the main menu headings.
4. Add the option for a user button to be defined as a "menu button" (i.e. a special category of user button). Menu buttons would popdown their menus on mouseover (after the first menu button had been clicked).
5. Enable submenu flyouts
The benefits
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Better use of screen space -with the menu and all or some of the buttons on one row.
Users can customize the menus any way they want (a major feature in itself).
Volunteers can translate complete menus and upload them to the forum.
No code changes would be required to facilitate translation of XYplorer's menus leaving only dialog and message boxes to be done.
Subsequent changes to the menu would not have to take translation into account.
When new features are added but a particular translation has not been updated, any user already familiar with menu customization can easily add their own to their menu.
Other considerations
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The original menu is not removed nor is it translated into other languages. It is merely hidden by default (i.e Alt+Up/#1061). It is always available in English on all future language versions of XYplorer. This makes providing help to non-English speakers on the forum much easier. You can always just give them menu items in English and let them find the corresponding term in their language by referencing the position in the English menu e.g. just tell them to press Alt+Up then click "Tools > Disconnect Network Drive" not "Herramientas > Desconectar unidad de red" or "Nástroje > Odpojit sítový disk".
It might be better to separate the toolbar section of the config file from the rest i.e. a separate toolbar.ini or menu.ini. This would make it easier for users to switch languages and to save and restore their own customized toolbars and menus.