[Lazarus] LCL Message handling

[Hans-Peter Diettrich]

Can somebody explain the purpose of e.g. WindowProc, WndProc and 
MainWndProc, in the LCL?

What's the purpose of TWinControl.MainWndProc, when it's never called or 
used otherwise, does nothing, and is not virtual?

In Delphi MainWndProc calls the handler assigned to WindowProc, enclosed 
in try-finally and try-except blocks. WindowProc typically is 
initialized with WndProc. Why is this implemented differently in the 
LCL, and how?

DoDi