I did more testing last night and resolved the crashing to this:

The visual class has to be an activex - based on OLE as baseclass. Add custom methods to class; does not matter if you have memberdata defined or not. Enable Intellisense. When you enter the following:

this.MyMethodName(

The editor will respond as expected - no C5 crash. However, if you use a WITH - ENDWITH construction like the following:

WITH this
  .MyMethodName(
ENDWITH

This will cause a C5 crash as soon as the opening parenthesis is entered. The intellisense will give the method name on picklist and the opening parenthesis will select the choice but it leads to a C5. It does not matter how many lines are between the WITH and the entry of the methodname. If you disable intellisense then no C5 crash will occur. If a class is based on a baseclass that is standard VFP (like combobox or textedit box) then the C5 does not occur (using the same method name) -- only occurs on baseclass of OLE.

Also, I have found that not all OLE classes will do this -- it seems to be limited to a few "lucky" ones.