Comment 13 for bug 855839

This is to be expected: When trying to snap Inkscape collects all items within snapping range, and for this it uses the bounding box. But because the bounding box also includes this useless page-size clipping path, it will consider all items for snapping as soon as you move into the page boundaries, instead of just the few rectangles near the mouse pointer. Subsequently, it will try to find intersections for 342 items (~suv's file), which constitute 341*340*339*...*2 = 10^717 combinations! Now let's just forget the fact that calculating intersections is inherently slow anyway ;-).

I will have a look if the bounding box calculation can be improved for cases like this, but this could be quite tricky.

BTW, this is a very nice use-case demonstrating why I've implemented the snap-delay. A snap delay > 0 allows you to move across the page because snapping will be on hold while you move, and Inkscape will remain responsive.