OS: Windows 10 Version 2004 - 64bit
When an image extends outside the XnView MP window, either horizontally or vertically (not both).
When the image is mouse dragged, then the pan tools view rectangle (red/white border) becomes offset.
Effect: Display glitch
To reproduce:
With a mouse button set to: Move picture
For example: Tools > Settings > Interface > Mouse > Right button [Move Picture]
(I don't remember if it's the default setting)
The issue is also reproducible when the Left mouse button is set to Move picture.
1. Open an image
2. If the pan tool isn't enabled, then enable it:
Tools > Settings > View (in the left panel) > View (tab) > [v] Show Pan tool
3. Zoom in on the image so that it's either, horizontally or vertically larger than the XnView MP window.
4. Left mouse drag on the pan tools view rectangle.
5. Right mouse drag (Move picture) to move the image.
Actual behaviour (bug

After step 3:
If the left and right sides of the image are outside the XnView MP window,
then the view rectangle on the pan tool is offset upwards.
The top of the view rectangle is on top of the pan tools top border,
and there's a gap between the bottom of the view rectangle and the bottom of the pan tool.
Even though the bottom of the image is visible.
After step 4:
The pan tools view rectangle doesn't have a offset,
and it matches the visible part of the image in the main window.
After step 5:
The pan tools view rectangle has the same offset as it did after step 3.
Alternating between steps 4 and 5 shows the offset occurring when the image is moved,
and the offset disappears when the pan tools view rectangle is moved.
When the following image sides are outside the XnView MP window,
then the pan tools view rectangle becomes offset in the direction:
- Top and bottom sides outside the window, view rectangle offset: Left
- Left and right sides outside the window, view rectangle offset: Up
- All sides outside the window, view rectangle offset: None
Expected behaviour:
When either the left and right, or the top and bottom sides of an image extend outside the XnView MP window.
Then the pan tools view rectangle should match the visible part of the image, without being offset.
As it currently does when all sides of an image is outside the XnView MP window.