When adding or editing a "Say Something with Text-To-Speech" action, starting a preview of the text and closing the window using the "OK" or "Cancel" buttons will throw the following exception:
"Invoke or BeginInvoke cannot be called on a control until the window handle has been created"
However, this only occurs when text is selected.
This bug seemed to only occur when editing, but that's because all text is selected by default when the window opens.
It also appears highlighting words that the TTS is speaking and restoring the selection afterward,
a feature that was apparently working in v1.5.8.20, is now broken(which is possibly why all text is selected by default).