FloatContainer and Floats with mouse positioning and resizing - a la TurboVision

I'd like to use a FloatContainer as a 'desktop' motif (MDI container), with the floats resizable and movable via the mouse. I'm going for the look and feel of character graphics applications from the DOS era.
Currently, enabling mouse support only allows one to focus a container, but not move it.

I think at least with existing features, it would be possible to at least have dynamic Window movement and resizing using arrow keys. The keybind callback would write to the top/left arguments to the focused Float somehow. A similar feature was available in TurboVision from a menu pick.

Here's an example of what I have so far in prompt toolkit.

And here are some examples of the type of user interface I'm trying to emulate. The Windows in these applications are movable using the mouse and keyboard.

VB 1.0 for DOS

Borland's TurboVision (C++) Demo Application

Start by tracing FloatContainer, its mouse-support behavior, and the keybind callback described in the issue. Determine how focused floats receive positioning and resizing events. Done means floats in a FloatContainer can be moved and resized with the mouse and keyboard in a TurboVision-style desktop layout.