I have two shapefile layers in a Qgis project that have problems with zooming. One is a line I copied/pasted in a new layer from a set of height contours and the other one is a polygon layer I created by dissolving all features in another layer.
In both cases, the layers won't display unless the entirety of the layer shows in the canvas. When I zoom in or drag the view, as soon as part of the layer is out of the canvas the entire layer disappears.
In the case of the polygon layer, if I delete it and generate it again it works properly, but when I start filling the rings it reaches a point when it stops working well (I want to end up with a single polygon enclosing all features in the original layer). I guess it must have to do with the geometry of the layer, but I haven't found the cause.
Both layers previously worked well, and removing them/adding them again doesn't fix the issue.
All other layers in the project work well (including the set of height contours and the polygons layer I used to generate the troublesome layers).
This issue has shown in both Qgis 2.4 and 2.6
Is there anything I'm doing wrong?