Refactored `DropDownListExample` for modularity and lifecycle management. Introduced `PopoverWrapper<TView>` to enable any `View` to function as a popover, along with `ViewPopoverExtensions` for a fluent API. Added `PopoverWrapperExample` project to demonstrate usage with examples like `ListView`, forms, and `ColorPicker`.
Enhanced `Shortcut` class with a configurable `MarginThickness` property. Updated `PopoverBaseImpl` to redraw UI on visibility changes. Added comprehensive unit tests for `PopoverWrapper` and extensions. Updated `Terminal.sln` to include the new project. Added detailed documentation in `README.md`.
Improved code maintainability, modularity, and user experience.
