Steve, I see now its a feedback thing in the lower right of taskbar. Maybe a bug.
Begin with a 800 x 600 page, set the origin to the top-left corner.
Place cursor on right side of page. When the cursor changes, the taskbar shows 800pix. As soon as the cursor is dragged, the taskbar feedback shows .5pix increments. The decimal amount varies depending upon the zoom level.
The page size in the options dialog always indicates whole pixels while dragging. (I've never had the dialog opening while dragging with the mouse before, otherwise, I would have stated the above posting differently. Sorry.
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