[Lazarus] Event with changed signature can be loaded without error

[Werner Pamler]

I don't know: is this changed or am I fooled by my memory? I was rather 
sure that when the signature of a published event is changed, forms 
saved with the old signature cannot be read without error. But now I 
notice that this is not true any more.

The version of TAChart which I just committed to trunk had to change the 
signature of the TChartDataPointDrawEvent event from

    procedure (ASender: TDataPointDrawTool) of object;

to

  procedure (ASender: TDataPointDrawTool;  ADrawer: IChartDrawer) of object;

Testing this with the demo in folder 
(lazarus)/components/tachart/demo/tools in which the event is handled I 
was expecting an error - but no, the program compiles and runs fine as 
if nothing had changed.

Am I missing something?