This doesn't really work for me: whenever I read articles on the internet, I tend to select text by double-clicking and dragging, which trigger the collapsation. Neat concept, though!
There's probably a way for me to not collapse on a double-click-and-drag. But you should consider switching over to single-click-and-drag! Saves loads of clicks over the course of a year!
Double-click and drag makes the selection be whole words, which saves time over having to find the start and end more precisely. (I actually often triple-click and drag, for selecting whole paragraphs)