Block dragging not working in IE10
I'm experiencing this issue on 126.96.36.199, and I also tested this on a fresh install of 188.8.131.52 - where the issue still occurs.
From what I can gather, the CSS property transform: matrix() is being used to move the draggable box, but it doesn't update any of the position values as you attempt to move it. It just hangs on the position where you first grabbed it.
The client my website is for is a stuck with using IE10, so simply upgrading to a modern browser is not an option for me, unfortunately.
Take a look at these stats:
I would show your client those stats, and convince them to switch to Chrome or Firefox.
I can confirm that blocks cannot be dragged in IE 10. They can be dragged in IE9 and IE11 - it makes me think there is a quirk in IE 10.
I agree that usage stats won't reflect that some large organizations use Internet Explorer.
One issue is that IE 10 is now end of life, as of January 12, 2016 it stopped receiving fixes, technical support, and security updates (with exceptions for some operating systems and special support arrangements). In all honesty, I am not sure how much energy will be devoted to fixing this.
A GitHub issue was created that you can comment on:
Blocks cannot be dragged or moved in edit mode using IE10 #5379
I agree with MrK that the C5 core team is probably not going to devote much energy to fixing this kind of edge case.
Maybe the script Github repo would be a good place to ask for a solution?