(I tried to stick to the rules and wanted to enter the irfanview version I am using in my profile, but 4.53 is not available)

Until a few days ago I used version 4.50.
In thumbnail view, after selecting a folder, I could use up and down keys to select the previous / next folder in the tree.

In 4.53, up key selects the last thumbnail in the selected folder, down key selects the first thumbnail.

To select the next folder, I now have to use the mouse to click on it.

I did not find any setting which might restore the previous key navigation in folder tree ...

How can I get back key navigation in folder tree of thumbnail viewer?

Thanks in advance!