Selectable list of lines
Inherits from Browser
The Hold_Browser class is a subclass of Browser which lets the user select a single item, or no items by clicking on the empty space. As long as the mouse button is held down the item pointed to by it is highlighted, and this highlighting remains on when the mouse button is released. Normally the callback is done when the user releases the mouse, but you can change this with the when property.
See Browser for methods to add and remove lines from the browser.