Polygonal viewport OSNAP 'bug'

I've had this issue before but never really investigated it further until today.

I use a lot of polygonal viewports to show twisting routes of water mains along a section of an OS map and add connection details in the remaining paper space areas.

What I've noticed when using this method is that OSNAPS still snap to the map features in the empty space, however, only within a rectangular area that would fit the extents of the polygonal viewport.

I'm not looking for a fix as it's not a major issue, but just thought I'd report it and see if anyone else has noticed it and knows why it happens?

Been like that for a while, AFAIK.

Irregularly shaped viewports are really rectangular viewports that have been clipped (masked). That clipping can be removed, leaving a rectangular viewport.

Not a bug, just the nature of the beast.

I generally avoid the non-rectangular viewports. With VPSYNC I find it easy to get the same desired result without the overhead the non-rectangular VP's bring. Your needs may not allow for multiple viewports but that is my work around.

Robdraw interesting about the clipping, a software developer once told me a trick he used was to make objects same color as screen background so did not see them was faster than going through turning them all off.