Further discoveries and clues...
Again... this is Win11 25H2, running FCXE specifically in user-mode where at least certain 3rd-party shell extensions will appear. Something about FCXE running in admin-mode which 100% prevents those 3rd-party shell extension entries from ever appearing in the right-click menu. And yet there are other 3rd-party products (e.g. Notepad++ and PowerISO) whose shell extensions will ALWAYS show up, no matter FCXE launched in user-mode or admin-mode.
So, I was working with MP4 files today, and wanted to look at the file properties of what I had produced with my edits. My normal tool for this is through MediaInfo, accessed through its "shell extension" from the right-click on the MP4 file appearing in a Windows File Explorer window.
Today, surprisingly, when I right-clicked on that MP4 file I did NOT see MediaInfo's usual entry in the popup context menu. In fact I didn't see any of the other usual suspects (i.e. other 3rd-party programs which I have installed and which themselves have their own shell extensions adding their entry to the popup menu) which also normally appear. Very abbreviated right-click menu. Very strange.
Then I had a recollection about something I recalled about the relevance (for FCXE I think?) of the relevance of the actual mouse cursor physical location relative to the file name text itself as it appears on that line in File Explorer (or FCXE?) when issuing the right-click (i.e. whether the cursor is physically on the left side of the line somewhere over the text of the file name vs. whether it is to the right somewhere over the blank space on the right of the text of the file name). I remembered something different about the right-click behavior depending on whether the mouse cursor was hovered toward the left and over text, or toward the right and over blank space, when the right-click was issued. Couldn't quite remember the details, but I did remember that cursor location was relevant to what got presented.
So still in File Explorer I repeated my right-click, this time having the mouse cursor hovered over the file name text. And sure enough there was an absolute difference in the contents of the popup menu. All of those expected additional 3rd-party program shell extension items now appeared, seemingly "collected at the bottom" of the menu.
Now this behavior is all brand new stuff with Win11, and specifically what Microsoft did new in 25H2 relative to lots of things like user programs being no longer allowed to do things they previously were allowed to do, pertaining to the taskbar, notification area, popup menus and shell extensions, etc., and what 3rd-party programs were allowed or no longer allowed to do, or maybe a new way that they now need to do things.
Now, trying the same thing in FCXE, varying the mouse cursor location to either be on the left side over the file name text or on the right side over the blank area on the line, there does not seem to be any difference in popup menu appearance. Same results (i.e. failure) as I've now shown earlier, where the first right-click does NOT show the expected items, but the second and subsequent right-clicks still within the same FCXE launch session DO show all of the expected items.
In my mind I somehow think this is DIFFERENT than it used to behave, where the left/right location of the mouse cursor WAS relevant to what was shown on the popup menu. But now with 25H2 this FCXE behavior no longer seems "sensitive to cursor location", but simply fails all the time to show those items on the first right-click but does show them on second and subsequent right-clicks.
Almost like they actually got discovered by that first right-click but too late in the popup menu formatting process to actually get formatted and appear. But because they had now actually been discovered (by that first right-click, but "late in the game"), they were actually stored somewhere making them residually now known going forward in the same FCXE launch session. This could explain how from all right-clicks after that first right-click, the second and subsequent right-clicks saw them (in their residually non-empty memory field locations) and thus now always presented them... even though they still were not actually in time by the current normal right-click logic but simply because they were actually discovered previously and residually remembered by that original first click. And so they now always get presented in all subsequent right-clicks still within the same FCXE launch session, where this residual knowledge remains residual throughout.
So I now notice that the list of 3rd-party programs is more than just WinRAR which is failing to present its shell extension on that first right-click of an FCXE user-mode launch session.
I now see that the list of right-click FCXE+25H2 mishandled programs also includes MediaInfo, Mp3Tag, BitDefender, and very likely more. There is also what looks like a Windows-added item about "Edit with Notepad".
