option to lock dimension - move a shape or selection only vertically or only horizontally

Yes, there is. On the Setup ribbon tab, make sure that the "Mouse keys" button is pressed (it is by default). Then, move the mouse over that shape until the "move" cursor appears - it should look like the regular big arrow cursor, but have small arrows pointing in 4 directions at the tip of the arrow. At this time normally you could press the left mouse button and while holding it, move the shape around.
 
Now: we will use arrow keys instead. While the "move" cursor is still showing, do not press any mouse keys - instead press the Enter key on the keyboard. This emulates pressing and holding the left mouse button. Still don't touch the mouse at all - just press the arrow keys on the keyboard (you may press and hold any of them) to move the shape in that direction. When done, press the Enter key again to "release" the shape.
 
Greg

It is exactly the same procedure. Just select an area, then move mouse cursor over it and proceed with the "arrow keys" instructions as described in the previous message.
 
Greg