Hi agmorgan

Binary Compatibility preserves the external signature of the control. This is the public interface. This is what any app using you control is looking for and know how to use. This means that any program that uses the control can continue to use it after you have made internal changes. You change anything in the control that is not public. You can even change how public functions work so long as you don't change their name, input parameters and return values.

However, this also means that binaray compatibilty can not be maintained if any public part of the control changes, for example, a new public function is added or the type of a public function parameter is changed. If you have make such changes you have to recompile the program that uses the control with the recompiled control.

No Compatabilty creates a control with an entirly new external signature. This means that any app using the control will not be able to find it. It will be looking for the signature that it was compiled with and won't be able to find it.

I'm not sure how to use project compatibilty. I use binary compatability exclusivly unless I'm forced to use no compatabilty due to a change in the external signature. Then I create the new control, addit back into the main app, and then switch back to Binary compatabilty.

In practice I create the control and then change its name to <ControlName>Master. I then set the binary compatabilty to this master control. This seems to save problems with setting compatabilty to a control I'm replacing.

Good Luck

FW