Toolkit method GarbageCollection has been deprecated starting with Toolkit 10 and has been removed in Toolkit 11. The recommended method to dispose of the Toolkit object is to wrap your Toolkit code in a USING statement or manually call the Dispose method.
Toolkit 10 and later versions no longer copy the Toolkit native DLLs to the Windows system folders. The Toolkit constructor must be called with the path to the native DLLs or place them in your applications working directory or the Windows system folders. GarbageCollect will only look for the native DLLs in the application working directory or the system folders. If called without the native DLLs in one of these locations you will see a System.ArgumentException: 'Core library not loaded parameter name Toolkit'.