Control/Shift/Up or down malfunctioning on sub-projects

Control/Shift/Arrow Up (or Arrow Down) seem fairly buggy when applied to sub-projects.

e.g. So if within a Project I have a number of sub-projects and if I try to move any give sub-project up or down the list of other sub-projects, by using Control/Shift/Arrow Up (or Arrow Down) unexpected things keep happening. I am hoping for items of the same level to simply swap places. However the entire sub-project seems to disappear completely until you reload the whole page.

This is v painful if (like me) you are in the habit of moving sub-projects around quite a lot to indicate relative priority between the sub-projects. Yes you can use the mouse but it’s about 10 times slower. Fixing this would be near the top of my priorities.