I imported shapefiles for N America and Europe (http://www.cdc.gov/search.do?action=search&queryText=shapefiles&x=14&y=7). But they do not display completely. Parts of the layer dissapear an re-apepar depending on the zoom level or the panned position in the Map windows.
The map projection was NAD27 polar sterographic
Is there a problem with the size or number of vertices of the shapefile? Or is this a problem with the polar projection (by the way, it is needed fro circumpolar maps). This is a real problem for someone like me that works on circumpolar phenomena.