std.signals crashes GtkD gui application when SpinButton tied to signal.

[Enjoys Math via Digitalmars-d-learn]

I have two spin buttons connected to the width and height of 2d 
objects in a scene.  Using

     mixin std.signals.Signal!(double, double) dimentionChanged;

and there is a growing delay that happens not caused by the 
rendering code, the transform code, or the triggering code (I 
used a timer to measure).

Then switching over to a D delegate, the issue went away.

It starts to freeze the gui app so that you can't do much at all.

Thus std.signals can't handle a large number of signals maybe 50 
/ second.  It causes some weird delays to happen.

Would anyone like to see my source code?

You need:
Visual D
GtkD-3.(latest) (32-bit)
Gtk Runtime