DOC: Add notes about changes to core and external DWM window manager

Luciano Notarfrancesco wrote to the ML

About my recent changes, some of them are 1) extensions to Theme to be able to customize some more aspects of how the windows and widgets look, or 2) fixes for small bugs that I found on the way, like misalignments of a few pixels between parts of a widget or a window. The motivation behind this was just to be able to implement a very minimalist look (borders of just 1 pixel, no decorations, no icons, no anything that I dont need and takes up screen real estate), and a sort of tiling dynamic window manager very much like http://dwm.suckless.org

https://github.com/len/Cuis-Smalltalk-DWM.

In order to implement this "window manager" as an external package with minimal changes to the core system, I decided to: 1) make the current Theme receive messages #windowOpen: #windowClosed: every time SystemWindows are open or closed, in order to give it a chance to implement window-management behaviour or delegate it to a proper window manager; 2) move the window-management keyboard shortcuts (like alt-w to close) to Theme, so it is all in one place, easy to change, and easy to make a Theme that delegates keyboard events to a proper window manager.

Again I did it like this in order to minimize changes to the core system. At the moment window management is in part implemented in SystemWindow, and also in HandMorph and Morph. I had to make some small modifications in order to get the desired behavior when using DWM, and keep the original behavior in the base system. Maybe in the long run we would want to have a WindowManager class that do this, handle keyboard events for the window-management shortcuts and receives #windowOpen: and #windowClosed:, etc. But I would like to think better about this before adding new concepts and complexity to the core.

Cuis-Smalltalk / Cuis-Smalltalk-Dev

DOC: Add notes about changes to core and external DWM window manager #78