Opening specific file formats

[shinerb]

I'm using psp 2020. When I open a new file, by default the drop=down menu in the bottom corner is set to 'All Files'. As I only want to view and open TIFFs I change the drop-down to TIFFs only, but after I've opened 2 or 3 files it reverts to 'All Files'. Is there a way of fixing this so I can only open a particular format indefinitely?

[Radim]

If it constantly reverts then keep in folder only TIFFs and other format put aside for a while, like subfolder.

[shinerb]

Yes, that's what I've started doing. I just wondered if there was a way of doing it within psp.