When coding Windows application with GUI, there is an issue about how long does it take to add lots of items (like hundreds or thousands) into a list view or tree view control. It is caused by redrawing the control after each operation. I've seen this annoying effect in may programs, including some serious, commercial ones. Apparently many programmers don't know there is a simple solution. But first a bit of background...
When coding games, we constantly spin inside a big loop and redraw whole screen every frame. Calculations are separated from rendering so we can, for example, build a list with thousands of items in the computation function and the visible part of the list will start being rendered since the first rendering function call after that. When coding windowed applications, nothing new is drawn onto the screen unless needed. We have to manually do it and we can call redrawing function any time. So how should a list control be refreshed when we add an item into it? It is done automatically after each insert, which is a good solution... unless we want to add hundreds of them.
So GUI library developers provide a functionality to temporarily disable redrawing of a control.