[Bug 39841] Double Commander context menus missing most entries

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=39841

--- Comment #6 from Damjan Jovanovic  ---
Let's examine the scarcity of menu options when right-clicking a file.

Starting as before, but now in platform/win/ushellcontextmenu.pas:
constructor TShellContextMenu.Create()
    calls GetShellContextMenu()
    calls GetForegroundContextMenu() 
    runs
        Folder.GetUIObjectOf(Handle, Files.Count, PItemIDList(List^),
IID_IContextMenu, nil, Result);
    which calls Wine's ShellFolder2_GetUIObjectOf() with IID_IContextMenu, in
dlls/shell32/shfldr_unixfs.c which runs:

---snip---
        if (IsEqualIID(&IID_IContextMenu, riid)) {
            return ItemMenu_Constructor((IShellFolder*)iface,
This->m_pidlLocation, apidl, cidl, riid, ppvOut);
---snip---

Once created, we go back to TShellContextMenu.Create(), which runs
    OleCheckUTF8(FShellMenu1.QueryContextMenu(FShellMenu, 0, 1, USER_CMD_ID -
1, UFlags));
    which is Wine's ItemMenu_QueryContextMenu() in
dlls/shell32/shlview_cmenu.c.

This seems to return an unpopulated menu. Then TShellContextMenu.Create() will
return, and TShellContextMenu.PopUp() will get called, which just adds the
"Actions" submenu with "View" and "Edit" subitems.

Where were the missing menu options meant to be added?

0024:trace:shell:ItemMenu_QueryContextMenu (0x6270108)->(0xd01e2 0 0x1 0xfff
0x14 )

uFlags were 0x14 == CMF_CANRENAME | CMF_EXPLORE

That idCmdLast == 0xfff seems to be wrong, as when I hack
ItemMenu_QueryContextMenu() to use 0xffff instead, I get the full list of
context menu items:

Open
Actions
Cut
Copy
Create Link
Delete
Rename
Properties

But why are they otherwise absent? That idCmdLast == 0xfff (or my "better"
0xffff) is passed to Shell_MergeMenus(). Is Shell_MergeMenus() behaving
incorrectly? Maybe it should ignore idCmdLast when the destination is empty?