From Xojo Documentation

Class (inherits from RuntimeException)

You tried to get the parent of a control using the Parent property of the Control class, but its parent is in a different window. The parent control must be in the same window as the control or the parent is the containing window, not another control.

CallStack Message Stack
ErrorNumber Stack
CallStack Stack

Sample Code

This example tries to capture an invalid parent control.

Me.Parent = SendDemoWindow.PushButton1

Exception err As InvalidParentException
MsgBox("An InvalidParentException occurred!")

See Also

Parent property of the Control class; Exception, Try statements; RuntimeException class.