Just upgraded from Dopus 11 to 12, really impressed with the new viewer/thumbnail functionality and now replaced xnview as my primary image browser.
One possible bug - if I enable left mouse click to expand/scroll within the viewer, then open a Nikon NEF file, the cursor doesn't turn to the expand/scroll icon and left clicking does nothing. If however the same folder has JPG files in and I scroll past a JPG, or start the viewer by opening a JPG, the next NEF file I encounter the expand/scroll works fine.
NEF and JPG should behave the same in the viewer from this point of view.
Expand/Scoll only kicks in if the image has been scaled down (i.e. <100% zoom). Otherwise it just scrolls the image around within the viewer window, without expanding it outside of it.
Could that be the difference between the two images you're seeing? Are you zooming in, changing to fit/grow to page mode, or resizing the window between changing images?
Thanks for the reply Leo, how you describe it was how I'd also expect it to work but that doesn't seem to the case here.
The issue appears to affect all my Nikon NEF files. In the screen shot below both files are the same dimensions, however if I double click the JPG images the viewer opens and my cursor changes and allows me to click to zoom. If I double click the NEF images the viewer opens but the cursor doesn't change and I'm unable to zoom. If once I'm in the viewer I mouse wheel up to a JPG then back to the NEF the cursor then allows me to zoom.
I also checked the default view size and in both cases it's set to Fit to Page.
I've uploaded 4 NEF files below, feel free to download them and give the a try: https://drive.google.com/open?id=1s4hfm1GLRnz3S27r4jxz9IBxdv3FGJ7V
1 photo is from my Nikon D70, the other 3 are from my Nikon D90, the same issue appears on all of my NEF files regardless of Camera.
Primary monitor resolution = 2650 x 1440
Second Monitor resolution = 1920 x 1080
Running Win10 x64, DPI is 100% (no scaling).
Dopus viewer always opens on the primary monitor regardless of which monitor is showing the main lister.
Dopus version 12.7 x64 Pro Edition build 6540.
Main config settings relating to viewing images that I've selected:
Prefs > File Operations > Double-Click on Files > Use internal picture viewer for > all recognised pictures.
Prefs > Viewer > Mouse Buttons > Wheel > Advance to next image
I've also added .nef file type to the File Types > File Type Groups > Images so the Tile view layout is displayed correctly for these files, but this issue is still present if I remove it from that group.
Please let me know if you need any additional information.
