When switching models in a ListView then not all the memory is reclaimed. In the attached example, clicking on the view will set it to be a much smaller model. Checking the memory usage in task manager it will only go down to 100mb from 400mb. Clicking again will call gc() a second time and this will claim another 10mb. However starting with the smaller model will only use about 30mb in total, therefore they seems to be a leak of about 80mb due to the number of items used.