RadRichTextBox uses MEF
to load most of the UI (plus some other, like spell checking dictionaries) components, providing extensibility point for replacing them. On RadRichTextBox.SatisfyImports call, MEF composition is triggered and tries to find suitable components to fill RadRichTextBox properties, for example RadRichTextBox.FindReplaceDialog. I am not sure what SciTech's .Net Memory Profiler, but maybe it somewhat changes the default MEF catalog. What you can do to check if this is the problem is to set the catalog to a list of predefined types, as described in this article
You can also try to play with profiler's options
, as it seems that garbage collection throws such exceptions
when the system is under heavy load.
the Telerik team