Every designed LCL form has a Designer of type TIDesigner. The IDE creates designers of type TComponentEditorDesigner defined in the IDEIntf unit componenteditors.
You get notified when a designer form is modified with this piece of code:
GlobalDesignHook.AddHandlerModified(@Extension.OnDesignerModified);
...but there is an issue here:
the designer is notified using only the Object Inspector!
Important note:
when you resize a component at design-time, you resize with the mouse, dragging the component, the designer is not notified!
Any idea?