v24 - Deleting first file does not update folder thumbnail

[masterjp]

I launched XnView in directory view.
I have several folders in the main directory.
I opened one of them and deleted the first
file in the folder. Until then, this file had
also served as the thumbnail for that folder.
After deleting the picture file, I went back to the parent
directory. The thumbnail for the
folder did not update automatically. Even
swiping down did not cause it to update.

It would be nice if the refresh happened automatically
or at least after swiping down.

After rotating the android device from portrait view to landscape view, the folder thumbnail gets black.