Might be suggested already, somewhere, some time ago, but here we go anyway:
just like you can now alias, copy a pattern-track block in the matrix through dragging the bottom border down with the mouse, be able to do something similar with a mouse selection in the pattern editor.
For example: have a few hi-hats programmed, select them, hover the mouse towards the border of the selection for it to change the mouse pointer, drag down the selection and the selected notes are copied in a ctrl+p like fashion for as long as you drag downwards.
I think this could be handy, even better if besides downwards this behavior would work in multiple angles, upwards & sidewards too!