In the preview window and full screen view mode, when I click and hold to zoom and pan on a picture which is larger than the screen, the picture pans one pixel for each pixel the mouse moves. The mouse effectively drags the picture 1:1 and the cursor can reach the edge of the screen while part of the picture is still off screen, halting the pan. To pan past this, we need to release the mouse button and click the picture nearer the edge, beginning the zoom/pan again.
Suggested behaviour
It would be better, I think (certainly for me), if the panning speed was proportional to the size of the image instead. So, no matter where on the image the zoom/pan was started by clicking, it would be possible to pan across the whole image, edge to edge, in one panning motion. This does not interfere with the positioning of the zoom when clicking, it would only change how much the image pans when the mouse is moved.
The only down side would be a lack of absolute precision in positioning the image (for instance it might be that moving the mouse one pixel moves the image ten pixels). I do not think this would be an issue in practice; it never has been for me before, working with very large images.
I guess I got used to this using a competitor's product, which uses the proportional method. I much prefer XNView MP, regardless
