Selection of text in cell by Shift-Arrow should be restricted to focussed cell

When you select code in a paragraph via keyboard (Shift-ArrowDown) the selection extends beyond the active cell into the next one.

This is especially annoying when you mark all code in a cell and the last code line is the last line in the cell since then the cursor jumps to the beginning of the next cell and Copy/Paste does not work then any more.

Requested Change:
Like with selection by mouse the scope of the selection by Shift-ArrowKey should be restricted to the current cell.