Instead of requiring the ctrl key to be held down, you can hover over any file or folder in a given folder to reveal a + or - sign. All you have to do is click that in order to select the folder. Do that for each file or folder you need, and then do whatever you want with your selection. There is one slight downside to this method. If you happen to mis-click, you'll still lose your selection up to that point. If you are using the ctrl method, then clicking outside of a folder by accident won't affect anything.