For a while since I've switched to Ubuntu from Windows, I've been wondering about this. In windows, you can select an item in a listbox, hold Ctrl+Shift, then select another item, and all the items between the two that you selected will also be selected (see the picture below). My problem is, in some cases I have a few hundred items to select out of thousands, and the only way to select them is to individually select each of them while holding Ctrl. Is there a way to enable this ability in Ubuntu (even if it's just for GTK programs)?
It does indeed work this way, except you don't click on the item that is already selected, you have to click on the last item that is not selected.
Interestingly, "last item" depends on whether selected the top set first or the bottom set. If you selected the bottom item first the the "last item" is actually the upper one of the group in between. It's kind of intuitive, but would be odd if the system you used previously works in a slightly different way.
It already does what you want. Select and item at the top of the list. Scroll down. Select and item at the bottom of the list while holding Ctrl. Now hold CtrlShift and click on the last unselected item and all the items in between will be selected.
Of course, you could also have just selected one item at the top, then CtrlShift clicked on the last item to achieve the same result. It appears to work exactly how you want it to.