I'm working in QGIS Hannover and have added some vector shapefiles to my project. Some of the data in the files won't show up in the viewport, leaving "holes" in the map. The same file contains both visible and "invisible" data.
A colleague of mine opened them in Geosecma (an ArcMap module) for me. She discovered that the data not showing up was displayed from empty categories in the attribute table. When she changed this, she could view the complete dataset in the viewport. So there's nothing wrong with the data.
I went back into QGIS and tried displaying from every available attribute, using Symbology. I even tried using the exact same file as my colleague instead of my own copy. It did not solve the problem.
I'm at a loss. Any ideas?