Dragging in the text area with the middle mouse button
creates a selection without moving the
caret. As soon as the mouse button is released, the selected text is
inserted at the caret position and the selection is deactivated.
This feature has two additional, more suttle behaviors:
- If there already is a selection when you start middle-dragging, the selection
will be replaced with the region you marked with the mouse.
- Holding down Control while dragging the middle mouse button marks a
rectangular area, and pastes it vertically at the caret location (or into the
current selection).