How do I ensure polygons are properly displayed when using 'on the fly' CRS transformations in QGIS 2.6?

Question

QuantumGIS 2.6.0 (Windows 7 64-bit)

I have created a PostgreSQL POLYGON as WGS84 (CRS EPSG:4326). The polygon is a series of points around (but not actually on) the edge of the map. This is a rectangle (see the first image below).

POLYGON((-179.9 -89.999,-179.8 -89.999,-179.7 -89.999...), 4326

I have changed the CRS 'on the fly' to World Robinson (CRS ESRI:54030). In the previous version of QGIS this would now display my polygon as the racetrack shape of the Robinson projection. In QGIS 2.6 the correct shape is only displayed when I toggle 'Toggle Editing'.

I believe that only the extreme points are being displayed, until I toggle editing, when it is using all of the points. I have also observed this behaviour in linestrings.

Why is this, and how can I get my desired behaviour? Any help gratefully received!

Update The polygon starts to render correctly as you zoom in.

Answer 1

Try turning off the automatic simplification for the layer:

1. Right click the layer and select "Properties"
2. Click the "Rendering" tab
3. Uncheck "Simplify geometry"

This feature can cause issues with certain projections, and I suspect that's what you're encountering.