Inconsistent Behavior For Nonstandard File Extension

[metal450]

XnView MP 0.93.1 64-bit for Windows.

1) Take a folder with a few jpgs, & rename their extensions to something else - i.e. .xxx.
2) Launch XnView MP (browser mode), & navigate to the directory. It's able to recognize the jpg image data & display them (metadata, preview, etc)
3) Switch to view mode (i.e. from the toolbar, Enter key, etc). It still shows the photo as expected.
4) Use the left & right keys. It's able to navigate between all the .xxx "jpgs" in the folder.

So far so good.

Now quit XnView MP. From Windows, double-click one of the .xxx files & open it in XnViewMP. It shows the image as expected - but this time, the left & right keys don't work to navigate between photos - it's stuck on just that one photo. But if you switch to Browser mode & then back to View mode again - now navigation starts working.

So essentially, you can't navigate between photos until you've "visited" browser mode at least once. That's the bug.

[xnview]

Thanks to your detailed description I can reproduce