Shift + RMB does only work from bottom issues to top issues, not from top to bottom (direction in which you select issues)
CTRL + Click to select multiple items works fine

When you select a cell, there is a blue marker visible, this is for copying the cells to other cells,
This works only from bottom to top, not top to bottom

Multi select cellt when keeping RMB presses is also broken when going from top to bottom

CTRL + C >> CTRL + V works fine

When you select a cell of the most bottom row, the blue marker is only partly visible, this is because the row where you can insert new issues is rendered on top of the marker