Actual Behavior

The editor's scroll is forced to place the cursor within a narrow vertical center upon keystroke.
The editor begins scrolling on selection drag outside a narrow vertical center.

Expected Behavior

The editor only scrolls on keystroke if the cursor is (or would become) not visible. When it does, it only moves scroll as far as necessary to make the cursor visible.
The editor begins scrolling on selection drag near the visual borders.

Start a new, empty session with code and create a new file.
Hold enter/return until there are enough lines to fully fill the editor's visual space.
OBSERVE: the new lines never reach the visual bottom of the editor, instead scrolling to keep the cursor nearer to vertical center.
Scroll the view so that the last line appears at the bottom of the editor, and place the cursor on the last line.
Press "A"
OBSERVE: the scroll position is moved, placing the cursor and "A" visually nearer to vertical center.
Place the cursor at the line currently at the top of the editor view and press "B"
OBSERVE: the scroll position is moved, placing the cursor and "B" visually nearer to vertical center.
Select the text on the line containing "B" and begin dragging the selection.
Drag it towards the bottom.
OBSERVE: scrolling begins while the drag point is still near vertical center, instead of beginning at the bottom of the editor
Drag it towards the top.
OBSERVE: scrolling begins while the drag point is still near vertical center, instead of beginning at the top of the editor.

Moving the cursor and typing causes the view to shift, causing disruption of typing.
The visual range of the editor is halved - I cannot type at the bottom of the editor while referencing text at the top of the editor.
The dragging of text permits a much smaller region to maneuver, making it difficult to position the text where desired.
Initiating dragging of text outside of the region causes complete loss of control.